Codeforces Round #501 (Div. 3)(ABCDE)

A. Points in Segments

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

You are given a set of $\mathrm{nn segments\; on\; the\; axis OxOx,\; each\; segment\; has\; integer\; endpoints\; between 11 and mm inclusive.\; Segments\; may\; intersect,\; overlap\; or\; even\; coincide\; with\; each\; other.\; Each\; segment\; is\; characterized\; by\; two\; integers lili and riri (1\le li\le ri\le m1\le li\le ri\le m)\; —\; coordinates\; of\; the\; left\; and\; of\; the\; right\; endpoints.}$

Consider all integer points between $\mathrm{11 and mm inclusive.\; Your\; task\; is\; to\; print\; all\; such\; points\; that\; don\text{'}t\; belong\; to\; any\; segment.\; The\; point xxbelongs\; to\; the\; segment [l;r][l;r] if\; and\; only\; if l\le x\le rl\le x\le r.}$

Input

The first line of the input contains two integers $\mathrm{nn and mm (1\le n,m\le 1001\le n,m\le 100)\; —\; the\; number\; of\; segments\; and\; the\; upper\; bound\; for\; coordinates.}$

The next $\mathrm{nn lines\; contain\; two\; integers\; each lili and riri (1\le li\le ri\le m1\le li\le ri\le m)\; —\; the\; endpoints\; of\; the ii-th\; segment.\; Segments\; may\; intersect,\; overlap\; or\; even\; coincide\; with\; each\; other.\; Note,\; it\; is\; possible\; that li=rili=ri,\; i.e.\; a\; segment\; can\; degenerate\; to\; a\; point.}$

Output

In the first line print one integer $\mathrm{kk —\; the\; number\; of\; points\; that\; don\text{'}t\; belong\; to\; any\; segment.}$

In the second line print exactly $\mathrm{kk integers\; in any order\; —\; the\; points\; that\; don\text{'}t\; belong\; to\; any\; segment.\; All\; points\; you\; print\; should\; be\; distinct.}$

If there are no such points at all, print a single integer $\mathrm{00 in\; the\; first\; line\; and\; either\; leave\; the\; second\; line\; empty\; or\; do\; not\; print\; it\; at\; all.}$

Examples

input

Copy

3 5
2 2
1 2
5 5

output

Copy

2
3 4 

input

Copy

1 7
1 7

output

Copy

0

Note

In the first example the point $\mathrm{11 belongs\; to\; the\; second\; segment,\; the\; point 22 belongs\; to\; the\; first\; and\; the\; second\; segments\; and\; the\; point 55belongs\; to\; the\; third\; segment.\; The\; points 33 and 44 do\; not\; belong\; to\; any\; segment.}$

In the second example all the points from $\mathrm{11 to 77 belong\; to\; the\; first\; segment.}$

区间中有多少个没有被遮住的数

#include <iostream>

using namespace std;
int a[1000];
int b[1000];
int n,m;
int main(){
    cin>>n>>m;
    for(int i=0;i<n;i++){
        int x,y;
        cin>>x>>y;
        for(int i=x;i<=y;i++)
            a[i]=1;
    }
    int ans = 0;
    int cnt = 0;
    for(int i=1;i<=m;i++){
        if(a[i]==0){
            b[ans++] = i;
            cnt++;
        }
    }
    cout<<cnt<<endl;
    for(int i=0;i<ans;i++){
        cout<<b[i]<<" ";
    }
    cout<<endl;
    return 0;
}

B. Obtaining the String

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

You are given two strings $\mathrm{ss and tt.\; Both\; strings\; have\; length nn and\; consist\; of\; lowercase\; Latin\; letters.\; The\; characters\; in\; the\; strings\; are\; numbered\; from 11 to nn.}$

You can successively perform the following move any number of times (possibly, zero):

• swap any two adjacent (neighboring) characters of $\mathrm{ss (i.e.\; for\; any i=\{1,2,\dots ,n-1\}i=\{1,2,\dots ,n-1\} you\; can\; swap sisi and si+1)si+1).}$

You can't apply a move to the string $\mathrm{tt.\; The\; moves\; are\; applied\; to\; the\; string ss one\; after\; another.}$

Your task is to obtain the string $\mathrm{tt from\; the\; string ss.\; Find\; any\; way\; to\; do\; it\; with\; at\; most 104104 such\; moves.}$

You do not have to minimize the number of moves, just find any sequence of moves of length ${\mathrm{104104 or\; less\; to\; transform ss into tt.}}^{}$

Input

The first line of the input contains one integer $\mathrm{nn (1\le n\le 501\le n\le 50)\; —\; the\; length\; of\; strings ss and tt.}$

The second line of the input contains the string $\mathrm{ss consisting\; of nn lowercase\; Latin\; letters.}$

The third line of the input contains the string $\mathrm{tt consisting\; of nn lowercase\; Latin\; letters.}$

Output

If it is impossible to obtain the string $\mathrm{tt using\; moves,\; print\; "-1".}$

Otherwise in the first line print one integer $\mathrm{kk —\; the\; number\; of\; moves\; to\; transform ss to tt.\; Note\; that kk must\; be\; an\; integer\; number\; between 00and 104104 inclusive.}$

In the second line print $\mathrm{kk integers cjcj (1\le cj<n1\le cj<n),\; where cjcj means\; that\; on\; the jj-th\; move\; you\; swap\; characters scjscj and scj+1scj+1.}$

If you do not need to apply any moves, print a single integer $\mathrm{00 in\; the\; first\; line\; and\; either\; leave\; the\; second\; line\; empty\; or\; do\; not\; print\; it\; at\; all.}$

Examples

input

Copy

6
abcdef
abdfec

output

Copy

4
3 5 4 5 

input

Copy

4
abcd
accd

output

Copy

-1

Note

In the first example the string $\mathrm{ss changes\; as\; follows:\; "abcdef" \to \to "abdcef" \to \to "abdcfe" \to \to "abdfce" \to \to "abdfec".}$

In the second example there is no way to transform the string $\mathrm{ss into\; the\; string tt through\; any\; allowed\; moves.}$

暴力交换就行了.不会超时.

#include <bits/stdc++.h>

using namespace std;
int a[10000];
int main(){
    int n;
    string s,ss;
    cin>>n;
    cin>>s>>ss;
    if(s==ss){
        cout<<"0"<<endl;
        return 0;
    }
    string st = s;
    sort(st.begin(),st.end());
    string stt = ss;
    sort(stt.begin(),stt.end());
    if(st != stt){
        cout<<"-1"<<endl;
        return 0;
    }
    int ans = 0;
    for(int i=0;i<n;i++){
        if(s[i]!=ss[i]){
            for(int j = i;j<n;j++){
                if(s[j] == ss[i]){
                    a[ans++] = j;
                    char c = s[j];
                    s[j] = s[j-1];
                    s[j-1] = c;
                    i--;
                    break;
                }
            }
        }
    }
    cout<<ans<<endl;
    for(int i=0;i<ans;i++)
        cout<<a[i]<<" ";
    cout<<endl;

    return 0;
}

C. Songs Compression

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Ivan has $\mathrm{nn songs\; on\; his\; phone.\; The\; size\; of\; the ii-th\; song\; is aiai bytes.\; Ivan\; also\; has\; a\; flash\; drive\; which\; can\; hold\; at\; most mm bytes\; in\; total.\; Initially,\; his\; flash\; drive\; is\; empty.}$

Ivan wants to copy all $\mathrm{nn songs\; to\; the\; flash\; drive.\; He\; can\; compress\; the\; songs.\; If\; he\; compresses\; the ii-th\; song,\; the\; size\; of\; the ii-th\; song\; reduces\; from aiai to bibi bytes\; (bi<aibi<ai).}$

Ivan can compress any subset of the songs (possibly empty) and copy all the songs to his flash drive if the sum of their sizes is at most $\mathrm{mm.\; He\; can\; compress any subset\; of\; the\; songs\; (not\; necessarily\; contiguous).}$

Ivan wants to find the minimum number of songs he needs to compress in such a way that all his songs fit on the drive (i.e. the sum of their sizes is less than or equal to $\mathrm{mm).}$

If it is impossible to copy all the songs (even if Ivan compresses all the songs), print "-1". Otherwise print the minimum number of songs Ivan needs to compress.

Input

The first line of the input contains two integers $\mathrm{nn and mm (1\le n\le 105,1\le m\le 1091\le n\le 105,1\le m\le 109)\; —\; the\; number\; of\; the\; songs\; on\; Ivan\text{'}s\; phone\; and\; the\; capacity\; of\; Ivan\text{'}s\; flash\; drive.}$

The next $\mathrm{nn lines\; contain\; two\; integers\; each:\; the ii-th\; line\; contains\; two\; integers aiai and bibi (1\le ai,bi\le 1091\le ai,bi\le 109, ai>biai>bi)\; —\; the\; initial\; size\; of\; the ii-th\; song\; and\; the\; size\; of\; the ii-th\; song\; after\; compression.}$

Output

If it is impossible to compress a subset of the songs in such a way that all songs fit on the flash drive, print "-1". Otherwise print the minimum number of the songs to compress.

Examples

input

Copy

4 21
10 8
7 4
3 1
5 4

output

Copy

2

input

Copy

4 16
10 8
7 4
3 1
5 4

output

Copy

-1

Note

In the first example Ivan can compress the first and the third songs so after these moves the sum of sizes will

be equal to $\mathrm{8+7+1+5=21\le 218+7+1+5=21\le 21.\; Also\; Ivan\; can\; compress\; the\; first\; and\; the\; second\; songs,\; then\; the\; sum\; of\; sizes\; will\; be}$

$\mathrm{equal 8+4+3+5=20\le 218+4+3+5=20\le 21.\; Note\; that\; compressing\; any\; single\; song\; is\; not\; sufficient\; to\; copy\; all\; the\; songs\; on\; the\; flash}$

$\mathrm{drive\; (for\; example,\; after\; compressing\; the\; second\; song\; the\; sum\; of\; sizes\; will\; be\; equal\; to 10+4+3+5=22>2110+4+3+5=22>21).}$

In the second example even if Ivan compresses all the songs the sum of sizes will be equal $\mathrm{8+4+1+4=17>168+4+1+4=17>16.}$

求最少需要压缩的数量.

这题贪心.不算难,但是哇了一次.

#include <bits/stdc++.h>
#define ll long long int
using namespace std;
ll a[1000006];

bool cmp(ll a,ll b){
    return a>b;
}

int main(){
    ll n,m;
    cin>>n>>m;
    ll ans = 0;
    ll an = 0;
    for(int i=0;i<n;i++){
        ll x,y;
        cin>>x>>y;
        ans+=y;
        an+=x;
        a[i] = x-y;
    }

    if(ans>m){
        cout<<"-1"<<endl;
        return 0;
    }
    if(an<=m){
        cout<<0<<endl;
        return 0;
    }
    if(ans==m){
        cout<<n<<endl;
        return 0;
    }
    sort(a,a+n,cmp);
    ll cnt = 0;
    // cout<<an<<endl;
    for(int i = 0;an>m&&i<n;i++){
        an-=a[i];
        cnt++;
    }
    cout<<cnt<<endl;
    return 0;
}

D. Walking Between Houses

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

There are $\mathrm{nn houses\; in\; a\; row.\; They\; are\; numbered\; from 11 to nn in\; order\; from\; left\; to\; right.\; Initially\; you\; are\; in\; the\; house 11.}$

You have to perform $\mathrm{kk moves\; to\; other\; house.\; In\; one\; move\; you\; go\; from\; your\; current\; house\; to\; some\; other\; house.\; You\; can\text{'}t\; stay\; where\; you\; are\; (i.e.,}$

$\mathrm{in\; each\; move\; the\; new\; house\; differs\; from\; the\; current\; house).\; If\; you\; go\; from\; the\; house xx to\; the\; house yy,\; the\; total\; distance\; you\; walked\; increases}$

$\mathrm{by |x-y||x-y| units\; of\; distance,\; where |a||a| is\; the\; absolute\; value\; of aa.\; It\; is\; possible\; to\; visit\; the\; same\; house\; multiple\; times\; (but\; you\; can\text{'}t\; visit\; the\; same\; house\; in\; sequence).}$

Your goal is to walk exactly $\mathrm{ss units\; of\; distance\; in\; total.}$

If it is impossible, print "NO". Otherwise print "YES" and any of the ways to do that. Remember that you should do exactly $\mathrm{kk moves.}$

Input

The first line of the input contains three integers $\mathrm{nn, kk, ss (2\le n\le 1092\le n\le 109, 1\le k\le 2\cdot 1051\le k\le 2\cdot 105, 1\le s\le 10181\le s\le 1018)\; —\; the\; number\; of\; houses,\; the\; number\; of\; moves}$

$\mathrm{and\; the\; total\; distance\; you\; want\; to\; walk.}$

Output

If you cannot perform $\mathrm{kk moves\; with\; total\; walking\; distance\; equal\; to ss,\; print\; "NO".}$

Otherwise print "YES" on the first line and then print exactly $\mathrm{kk integers hihi (1\le hi\le n1\le hi\le n)\; on\; the\; second\; line,\; where hihi is\; the\; house\; you\; visit\; on\; the ii-th\; move.}$

For each $\mathrm{jj from 11 to k-1k-1 the\; following\; condition\; should\; be\; satisfied: hj\ne hj+1hj\ne hj+1.\; Also h1\ne 1h1\ne 1 should\; be\; satisfied.}$

Examples

input

Copy

10 2 15

output

Copy

YES
10 4 

input

Copy

10 9 45

output

Copy

YES
10 1 10 1 2 1 2 1 6 

input

Copy

10 9 81

output

Copy

YES
10 1 10 1 10 1 10 1 10 

input

Copy

10 9 82

output

Copy

NO

 仔细一点写就能写出来,注意特殊情况.

#include <iostream>
#define ll long long int
using namespace std;

ll n,k,s;
int main(){
    cin>>n>>k>>s;
    if((n-1)*k<s||k>s){
        cout<<"NO"<<endl;
        return 0;
    }
    ll cnt = s%k;
    ll ans = (s/k) + (cnt>0?1:0);
    cout<<"YES"<<endl;
    if(cnt==0){
        ll index = 1;
        for(ll i=0;i<k;i++){
            if(i%2==0){
                cout<<index+ans<<" ";
            }else{
                cout<<index<<" ";
            }
        }
        cout<<endl;
        return 0;
    }
    ll index = 1;
    ll pos = 1;
    for(ll i=0;i<cnt;i++){
        if(i%2==0){
            cout<<index+ans<<" ";
            pos = index+ans;
        }else{
            cout<<index<<" ";
            pos = index;
        }
    }
    ans--;
    if(pos==index){
        ll l = 0;
        for(ll i=cnt;i<k;i++){
            if(l%2==0){
                cout<<pos+ans<<" ";
            }else{
                cout<<pos<<" ";
            }
            l++;
        }
    }else{
        ll l = 0;
        for(ll i=cnt;i<k;i++){
            if(l%2==0){
                cout<<pos-ans<<" ";
                pos = pos-ans;
            }else{
                cout<<pos+ans<<" ";
                pos = pos+ans;
            }
            l++;
        }
    }
    cout<<endl;
    return 0;
}

E1. Stars Drawing (Easy Edition)

time limit per test

3 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

A star is a figure of the following type: an asterisk character '*' in the center of the figure and four rays (to the left, right, top, bottom) of the same positive length. The size of a star is the length of its rays. The size of a star must be a positive number (i.e. rays of length $\mathrm{00 are\; not\; allowed).}$

Let's consider empty cells are denoted by '.', then the following figures are stars:

The leftmost figure is a star of size $\mathrm{11,\; the\; middle\; figure\; is\; a star of\; size 22 and\; the\; rightmost\; figure\; is\; a star of\; size 33.}$

You are given a rectangular grid of size $\mathrm{n\times mn\times m consisting\; only\; of\; asterisks\; \text{'}*\text{'}\; and\; periods\; (dots)\; \text{'}.\text{'}.\; Rows\; are\; numbered\; from 11 to nn,\; columns\; are\; numbered\; from 11 to mm.\; Your\; task\; is\; to\; draw\; this\; grid\; using any number\; of stars or\; find\; out\; that\; it\; is\; impossible. Stars can\; intersect,\; overlap\; or\; even\; coincide\; with\; each\; other.\; The\; number\; of stars in\; the\; output\; can\text{'}t\; exceed n\cdot mn\cdot m.\; Each\; star\; should\; be\; completely\; inside\; the\; grid.\; You\; can\; use\; stars\; of\; same\; and\; arbitrary\; sizes.}$

In this problem, you do not need to minimize the number of stars. Just find any way to draw the given grid with at most $\mathrm{n\cdot mn\cdot m stars.}$

Input

The first line of the input contains two integers $\mathrm{nn and mm (3\le n,m\le 1003\le n,m\le 100)\; —\; the\; sizes\; of\; the\; given\; grid.}$

The next $\mathrm{nn lines\; contains mm characters\; each,\; the ii-th\; line\; describes\; the ii-th\; row\; of\; the\; grid.\; It\; is\; guaranteed\; that\; grid\; consists\; of\; characters\; \text{'}*\text{'}\; and\; \text{'}.\text{'}\; only.}$

Output

If it is impossible to draw the given grid using stars only, print "-1".

Otherwise in the first line print one integer $\mathrm{kk (0\le k\le n\cdot m0\le k\le n\cdot m)\; —\; the\; number\; of stars needed\; to\; draw\; the\; given\; grid.\; The\; next kk lines\; should\; contain\; three\; integers\; each\; — xjxj, yjyj and sjsj,\; where xjxj is\; the\; row\; index\; of\; the\; central star character, yjyj is\; the\; column\; index\; of\; the\; central star character\; and sjsj is\; the\; size\; of\; the star.\; Each star should\; be\; completely\; inside\; the\; grid.}$

Examples

input

Copy

6 8
....*...
...**...
..*****.
...**...
....*...
........

output

Copy

3
3 4 1
3 5 2
3 5 1

input

Copy

5 5
.*...
****.
.****
..**.
.....

output

Copy

3
2 2 1
3 3 1
3 4 1

input

Copy

5 5
.*...
***..
.*...
.*...
.....

output

Copy

-1

input

Copy

3 3
*.*
.*.
*.*

output

Copy

-1

Note

In the first example the output

2
3 4 1
3 5 2

is also correct.

数据量小,暴力前缀

#include <iostream>

using namespace std;

char c[105][105];
int a[105][105];
bool vis[105][105];
int dis[4][2]={0,1,0,-1,1,0,-1,0};
int main(){
    int x,y;
    cin>>x>>y;
    for(int i=1;i<=x;i++){
        for(int j=1;j<=y;j++){
            cin>>c[i][j];
        }
    }
    bool flag = true;
    for(int i=1;i<=x;i++){
        int ans = 0;
        for(int j = 1;j<=y;j++){
            if(c[i][j]=='*'){
                ans++;
                flag = false;
            }else{
                ans=0;
            }
            a[i][j] = ans;
        }
    }
    if(flag){
        cout<<"0"<<endl;
        return 0;
    }

    for(int i=1;i<=x;i++){
        int ans = 0;
        for(int j = y;j>=1;j--){
            if(c[i][j]=='*'){
                ans++;
            }else{
                ans=0;
            }
            a[i][j] = min(a[i][j],ans);
        }
    }

    for(int i=1;i<=y;i++){
        int ans = 0;
        for(int j = x;j>=1;j--){
            if(c[j][i]=='*'){
                ans++;
            }else{
                ans=0;
            }
            a[j][i] = min(a[j][i],ans);
        }
    }
    int cnt = 0;
    for(int i=1;i<=y;i++){
        int ans = 0;
        for(int j = 1;j<=x;j++){
            if(c[j][i]=='*'){
                ans++;
            }else{
                ans=0;
            }
            a[j][i] = min(a[j][i],ans);
            if(a[j][i]>1){
                cnt++;
                vis[j][i] = 1;
                int x = j,y = i;
                for(int k=0;k<4;k++){
                    int xx = x,yy = y;
                    for(int p = 1;p<a[j][i];p++){
                        xx = xx + dis[k][0];
                        yy = yy + dis[k][1];
                        vis[xx][yy] = 1;
                    }
                }
            }


        }
    }
    if(cnt==0){
        cout<<"-1"<<endl;
        return 0;
    }
    bool ttt = true;
    for(int i=1;i<=x;i++){
        for(int j = 1;j<=y;j++){
            if(c[i][j]=='*'&&vis[i][j]==0){
                ttt = false;
                break;
            }
        }
        if(!ttt) break;
    }
    if(!ttt){
        cout<<"-1"<<endl;
        return 0;
    }
    cout<<cnt<<endl;
    for(int i=1;i<=x;i++){
        for(int j = 1;j<=y;j++){
            if(a[i][j]>1&&c[i][j]=='*'){
                cout<<i<<" "<<j<<" "<<a[i][j]-1<<endl;
            }
        }
    }
    return 0;
}

E2. Stars Drawing (Hard Edition)

time limit per test

3 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

A star is a figure of the following type: an asterisk character '*' in the center of the figure and four rays (to the left, right, top, bottom) of the same positive length. The size of a star is the length of its rays. The size of a star must be a positive number (i.e. rays of length $\mathrm{00 are\; not\; allowed).}$

Let's consider empty cells are denoted by '.', then the following figures are stars:

The leftmost figure is a star of size $\mathrm{11,\; the\; middle\; figure\; is\; a star of\; size 22 and\; the\; rightmost\; figure\; is\; a star of\; size 33.}$

You are given a rectangular grid of size $\mathrm{n\times mn\times m consisting\; only\; of\; asterisks\; \text{'}*\text{'}\; and\; periods\; (dots)\; \text{'}.\text{'}.\; Rows\; are\; numbered\; from 11 to nn,\; columns\; are\; numbered\; from 11 to mm.\; Your\; task\; is\; to\; draw\; this\; grid\; using any number\; of stars or\; find\; out\; that\; it\; is\; impossible. Stars can\; intersect,\; overlap\; or\; even\; coincide\; with\; each\; other.\; The\; number\; of stars in\; the\; output\; can\text{'}t\; exceed n\cdot mn\cdot m.\; Each\; star\; should\; be\; completely\; inside\; the\; grid.\; You\; can\; use\; stars\; of\; same\; and\; arbitrary\; sizes.}$

In this problem, you do not need to minimize the number of stars. Just find any way to draw the given grid with at most $\mathrm{n\cdot mn\cdot m stars.}$

Input

The first line of the input contains two integers $\mathrm{nn and mm (3\le n,m\le 10003\le n,m\le 1000)\; —\; the\; sizes\; of\; the\; given\; grid.}$

The next $\mathrm{nn lines\; contains mm characters\; each,\; the ii-th\; line\; describes\; the ii-th\; row\; of\; the\; grid.\; It\; is\; guaranteed\; that\; grid\; consists\; of\; characters\; \text{'}*\text{'}\; and\; \text{'}.\text{'}\; only.}$

Output

If it is impossible to draw the given grid using stars only, print "-1".

Otherwise in the first line print one integer $\mathrm{kk (0\le k\le n\cdot m0\le k\le n\cdot m)\; —\; the\; number\; of stars needed\; to\; draw\; the\; given\; grid.\; The\; next kk lines\; should\; contain\; three\; integers\; each\; — xjxj, yjyj and sjsj,\; where xjxj is\; the\; row\; index\; of\; the\; central star character, yjyj is\; the\; column\; index\; of\; the\; central star character\; and sjsj is\; the\; size\; of\; the star.\; Each star should\; be\; completely\; inside\; the\; grid.}$

Examples

input

Copy

6 8
....*...
...**...
..*****.
...**...
....*...
........

output

Copy

3
3 4 1
3 5 2
3 5 1

input

Copy

5 5
.*...
****.
.****
..**.
.....

output

Copy

3
2 2 1
3 3 1
3 4 1

input

Copy

5 5
.*...
***..
.*...
.*...
.....

output

Copy

-1

input

Copy

3 3
*.*
.*.
*.*

output

Copy

-1

Note

In the first example the output

2
3 4 1
3 5 2

is also correct.

 加大了数据量

#include <bits/stdc++.h>
using namespace std;
char c[1005][1005];
int vis[1005][1005];
int n,m;
struct Node{
    int x,y,index;
}node[1000005];
int pos = 0;
int main(){
    scanf("%d%d",&n,&m);
    for(int i=0;i<n;i++){
        scanf("%s",&c[i]);
    }
    for(int i=1;i<n-1;i++){
        for(int j = 1;j<m-1;j++){
            if(c[i][j] == '*'){
                int cnt = 1;
                bool flag = true;
                while(flag){
                    int xx = i,yy = j;
                    if(xx-cnt>=0&&xx+cnt<n&&yy-cnt>=0&&yy+cnt<m){
                        if(c[xx-cnt][yy]!='*'||c[xx+cnt][yy]!='*'||c[xx][yy-cnt]!='*'||c[xx][yy+cnt]!='*'){
                            flag = false;
                            break;
                        }else{
                            vis[xx-cnt][yy] =vis[xx+cnt][yy] =vis[xx][yy-cnt] =vis[xx][yy+cnt] = 1;
                        }
                    }else{
                        flag = false;
                        break;
                    }
                        cnt++;
                }
                if(cnt>1){
                    node[pos].x = i+1;
                    node[pos].y = j+1;
                    node[pos++].index = cnt-1;
                    vis[i][j] = 1;
                }
            }
        }
    }
    for(int i=0;i<n;i++){
        for(int j = 0;j<m;j++){
            if(c[i][j]=='*'&&vis[i][j]==0){
                printf("-1
");
                return 0;
            }
        }
    }
    printf("%d
",pos);
    for(int i=0;i<pos;i++){
        printf("%d %d %d
",node[i].x,node[i].y,node[i].index);
    }
    return 0;
}