North America Qualifier (2015)

https://icpc.baylor.edu/regionals/finder/north-america-qualifier-2015

一个人打。。。。

B

概率问题公式见代码

#include <cstdio>
#include <cstring>
#include <iostream>
#include <queue>
#include <stack>
#include <vector>
#include <algorithm>
using namespace std;
#define clc(a,b) memset(a,b,sizeof(a))
#define inf 0x3f3f3f3f
const int N=10010;
const int MOD = 1e9+7;
#define LL long long
void fre() {
    freopen("in.txt","r",stdin);
}
 
inline int r(){
    int x=0,f=1;char ch=getchar();
    while(ch>'9'||ch<'0'){if(ch=='-') f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
 
int countt;
int  comb1(int m,int k)
{     
    int i;
    for (i=m;i>=k;i--)
    {
        if (k>1)
        {
            comb1(i-1,k-1);
        }
        else
        { 
            countt++;
        }
    }
    return countt;           
}
 
int main(){
    // fre();
    int T;
    int R,s,x,y,w;
    T=r();
    while(T--){
        double p1=0.0;
        int num;
       cin>>R>>s>>x>>y>>w;
       double p=(s-R+1)*1.0/s;
       double ans=0.0;
       for(int i=x;i<=y;i++){
           int c=y-i;
           p1=1.0;
           double p2=1.0-p;
           while(c--){
               p1*=p2;
           }
           int cc=i;
           double P=1.0;
           for(int j=1;j<=i;j++){
              P*=p;
           }
           // cout<<i<<" "<<P<<endl;
           countt=0;
           num=comb1(y,i);
           // cout<<P<<" "<<p1<<" "<<num<<endl;
          ans+=P*p1*num;
       }
       // cout<<ans<<endl;
       if(ans*w>1)
        printf("yes
");
       else
        printf("no
");
    }
    return 0;
}

F

水题

输出字符串中缺少的字母

#include<cstdio>
#include<cstring>
#include<iostream>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;
#define clc(a,b) memset(a,b,sizeof(a))
#define inf 0x3f3f3f3f
const int N=10010;
const int MOD = 1e9+7;
#define LL long long
void fre(){freopen("in.txt","r",stdin); }
// inline int r(){
//     int x=0,f=1;char ch=getchar();
//     while(ch>'9'||ch<'0'){if(ch=='-') f=-1;ch=getchar();}
//     while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
//     return x*f;
// }
int a[30];
char ans[30];
int main()
{
     
    int T;
    scanf("%d",&T);
    getchar();
    while(T--)
    {
        clc(a,0);
        clc(ans,0);
        string s;
        getline(cin,s);
        for(int i = 0; i < s.length(); i ++){
            if(s[i] >= 'a' && s[i] <= 'z')
            a[s[i] - 'a'] ++;
            if(s[i] >= 'A' && s[i] <= 'Z')
            a[s[i] - 'A'] ++;
        }
        int k = 0;
        for(int i  = 0; i < 26; i ++){
            if(!a[i]){
                ans[k++] = i + 'a';
            }
        }
        if(k ==0) {
            printf("pangram
");
        }
        else{
            printf("missing ");
            for(int i = 0; i< k;  i ++){
                printf("%c",ans[i]);
            }
            printf("
");
        }
    }
    return 0;
}

G

过河的经典问题

多个人过河每次船上必须有一人问最短时间

#include <cstdio>
#include <cstring>
#include <iostream>
#include <queue>
#include <stack>
#include <vector>
#include <algorithm>
using namespace std;
#define clc(a,b) memset(a,b,sizeof(a))
#define inf 0x3f3f3f3f
const int N=10010;
const int MOD = 1e9+7;
#define LL long long
void fre() {
    freopen("in.txt","r",stdin);
}
 
inline int r(){
    int x=0,f=1;char ch=getchar();
    while(ch>'9'||ch<'0'){if(ch=='-') f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
 
int TravelBridge(std::vector<int> times)
{
    size_t length = times.size();
    if(length <= 2)
        return times[length-1];
    else if(length == 3)
    {
        return times[0] + times[1] + times[2];
    }
    else
    {
        int totaltime = 0;
        int a = times[0];
        int b = times[1];
        int z = times[length-1];
        int y = times[length-2];
        if(b*2 < a + y)
        {
            times.erase(times.end()-1);
            times.erase(times.end()-1);
            totaltime += b + a + z + b + TravelBridge(times);
        }
        else
        {
            times.erase(times.end()-1);
            totaltime += z + a + TravelBridge(times);
        }
        return totaltime;
    }
}
 
int main(){
    int n;
    n=r();
    vector<int> v;
    for(int i=0;i<n;i++){
        int x;
        x=r();
        v.push_back(x);
    }
    sort(v.begin(),v.end());
    int ans=TravelBridge(v);
    printf("%d
",ans);
    return 0;
}

H

水题

旋转矩阵再输出

#include<cstdio>
#include<cstring>
#include<iostream>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;
#define clc(a,b) memset(a,b,sizeof(a))
#define inf 0x3f3f3f3f
const int N=10010;
const int MOD = 1e9+7;
#define LL long long
void fre() {
    freopen("in.txt","r",stdin);
}
 
inline int r(){
    int x=0,f=1;char ch=getchar();
    while(ch>'9'||ch<'0'){if(ch=='-') f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
 
char s[10010];
char a[110][110];
int main() {
    // fre();
    int T;
    T=r();
    // getchar();
    while(T--) {
        scanf("%s",s);
        int len = strlen(s);
        int q = 0;
        for(; ; q ++) {
            if(q * q >= len) {
                break;
            }
        }
        // cout<<s[0]<<endl;
        int pos;
        for(int i = 0; i < q; i ++) {
            for(int j = 0; j < q ; j ++) {
                pos = i * q + j;
                if(pos >= len) {
                    a[i][j] = '*';
                } else {
                    a[i][j] = s[pos];
                }
            }
        }
        // printf("%c
",a[0][0]);
        // for(int i=0;i<q;i++){
        //     for(int j=0;j<q;j++){
        //         printf("%c ",a[i][j]);
        //     }
        //     printf("
");
        // }
        for(int j = 0; j < q ; j ++) {
            for(int i = q - 1; i >= 0; i --) {
                if(a[i][j] != '*')
                    printf("%c",a[i][j]);
            }
        }
        printf("
");
    }
    return 0;
}

J

把单词映射成数字

从起点到终点搜索

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <list>
#include <map>
#include <stack>
#include <vector>
#include <cstring>
#include <sstream>
#include <string>
#include <cmath>
#include <queue>
using namespace std;
#define clc(a,b) memset(a,b,sizeof(a))
#define inf 0x3f3f3f3f
const int N=10010;
const int MOD = 1e9+7;
#define LL long long
void fre() {
    freopen("in.txt","r",stdin);
}
inline int r() {
    int x=0,f=1;
    char ch=getchar();
    while(ch>'9'||ch<'0') {
        if(ch=='-') f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9') {
        x=x*10+ch-'0';
        ch=getchar();
    }
    return x*f;
}
 
int a[35][35] = {0};
int p[35];
string s[35];
int n;
int ans[100];
bool idx[35] = {false};
int num = 1;
map<string,int> mapp;
 
void dfs(int u,int v) {
    if(u == v)
        return;
    idx[u] = true;
    for(int i = 1; i <= num; i ++) {
        if(a[u][i] == 1 && idx[i] == false) {
            p[i] =u;
            dfs(i,v);
        }
    }
    idx[u] = false;
}
 
int main() {
    clc(a,0);
    mapp.clear();
    n=r();
    // getchar();
    string line,x;
    string s1,s2;
    int k = 0;
    int t;
    bool flag = false;
    int u,v;
    for(int i =0; i < n; i ++) {
        getline(cin,line);
        stringstream ss(line);
        ss>>x;
        if(mapp[x] == 0) {
            mapp[x] = num;
            s[num] = x;
            num ++;
        }
        u = mapp[x];
        while(ss >> x) {
            if(mapp[x] == 0) {
                mapp[x] = num;
                s[num] = x;
                num ++;
            }
            v = mapp[x];
            a[u][v] = 1;
            a[v][u] = 1;
        }
    }
    cin>>s1>>s2;
    if(mapp[s1] == 0) {
        mapp[s1] = num;
        num ++;
    }
    u= mapp[s1];
    if(mapp[s2] == 0) {
        mapp[s2] = num;
        num ++;
    }
    v = mapp[s2];
    dfs(u,v);
    p[u] = -1;
    t = v;
    while(t != -1) {
        ans[k ++] = t;
        if(t == 0) {
            flag = true;
            break;
        }
        t = p[t];
    }
    if(flag == true) {
        printf("no route found
");
        return 0;
    }
    for(int i = k - 1; i >= 1; i --) {
        cout<<s[ans[i]]<<" ";
    }
    cout<<s[v]<<endl;
 
}

一个人打也挺好玩的