2017 Multi-University Training Contest

一场挺傻逼的比赛。。。。被一群省队学弟吊起来打。250/735

惨哦。

1002 Build a tree 【待补】

暴力建图题，好像坑点较多。

1005 Euler theorem

简单签到

#include <bits/stdc++.h>
using namespace std;
int T;
int main()
{
    scanf("%d",&T);
    while (T--) {
        int a;
        cin>>a;
        cout<<(a-1)/2+2<<endl;
    }
    return 0;
}

1006 Free from square  【补】

据说和NOI题很像，后来看了看题解，分组背包+状压

#include <bits/stdc++.h>
const int mod = 1e9+7;
const double ex = 1e-10;
#define inf 0x3f3f3f3f
using namespace std;
int prim[600],vis[600];
long long val[555];
int temp[10] = {2,3,5,7,11,13,17,19};
int dp[2][555][555];
int cnt = 0;
int N,K,now;
void init(){
    for (int i = 2; i<=500;i++){
        if (vis[i])continue;
        if (i>19) prim[++cnt] = i;
        for (int j = i+i;j <= 500; j+=i) vis[j] = 1;
    }
}
long long  getval(int t){
    long long ans = 1;
    for (int i = 0; i<8;i++){
        if (t%2) ans*=temp[i];
        t/=2;
    }
    return ans;
}
int main()
{
    int T;
    cin >> T;
    init();
    //cout << getval((1<<8)-1) ;
    for (int i = 0;i<(1<<8) ; i++) val[i] = getval(i);
    while (T--)
    {
        cin >> N >> K;
        memset(dp,0,sizeof(dp));
        now = 1;
        dp[1][0][0] = 1;
        for (int i = 1; i<=cnt && prim[i]<=N ;i++){ //枚举组
            now = !now;
            for (int k = 0;k<(1<<8);k++)
                for (int t = 0;t<=K;t++)
                    dp[now][t][k] = dp[!now][t][k]; //转移不选择的状态
            for (int k = 0 ; k <(1<<8);k++){        //枚举小质数状态
                if (val[k]*prim[i] > (long long)N ) continue;
                for (int j = 0 ; j < (1<<8) ; j++){ //枚举转移状态
                    if ((j&k)!=0) continue;
                    for (int t = 1;t <= K; t++){    //枚举数字个数
                        dp[now][t][(j|k)] =  (dp[now][t][(j|k)] + dp[!now][t-1][j]) % mod;
                    }
                }
            }
        }
        for (int k = 1; k<(1<<8);k++){
            if (val[k] > (long long)N) continue;
            for  (int j = 0;j<(1<<8);j++){
                if ((j&k)!=0) continue;
                for (int t = 1;t<=K;t++)
                    dp[now][t][j|k] =  (dp[now][t][j|k] + dp[now][t-1][j]) % mod;
            }
        }
        int ans = 0;
        for (int i = 1;i<=K;i++){
            for (int j = 0 ;j<(1<<8) ; j++){
                if (i<K) dp[now][i][j] = (dp[now][i][j] * 2) % mod; //是否有1
                ans = (ans + dp[now][i][j]) % mod;
            }
        }
        cout <<ans+1<<endl; // 单独一个1
    }
    return 0;
}

1008 Hard challenge

极角排序，然后两指针check扫一遍，竟然1A了。

#include <bits/stdc++.h>
const long long mod = 1e9+7;
const double ex = 1e-10;
#define inf 0x3f3f3f3f
using namespace std;
struct node
{
    long long x,y;
    int val;
    double c;
    int p;
}P[50034];
int N;
long long sum[100034];
bool pd(int a,int b)
{
    if (b>N)b-=N;

    return ((P[a].x*P[b].y -  P[a].y * P[b].x) > 0);
}
bool cmp(node a,node b)
{
    if (a.p == b.p )
    {
        if (a.p == 1)
        {
            return a.c > b.c;
        }
        else return a.c < b.c;
    }
    return a.p > b.p;
}
int main()
{
    int T;
    //freopen ("in.txt","r",stdin);
    scanf("%d",&T);
    while (T--)
    {

        scanf("%d",&N);
        memset(sum,0,sizeof(sum));
        for (int i = 1; i<=N; i++)
        {
            scanf("%I64d%I64d%d",&P[i].x,&P[i].y,&P[i].val);
            if (P[i].y >=0 ) P[i].p = 1;
            else P[i].p = 0;
            if (P[i].y == 0 && P[i].x < 0) P[i].p = 0;
            P[i].c = P[i].x / sqrt( ((1.0*P[i].x)*(1.0*P[i].x)) + ((1.0*P[i].y)*(1.0*P[i].y)));
        }
        if (N==1) {
            puts("0");
            continue;
        }
        sort(P+1,P+N+1,cmp);
        for (int i = 1; i<=N;i++)
            sum[i] = sum[i-1] + P[i].val;
        for (int j = 1; j<=N; j++)
            sum[N+j] = sum[N+j-1] + P[j].val;
        int r;
        for (r = 1; r<=N && P[r].p >=1;r++);
        int l = 1;
        long long ans = 0;
        r--;
        for (int i = 1; i<=N; i++)
        {
            while (pd(i,r)) r++;
            if (i==r||i+N==r) r++;
            ans = max((sum[r-1] - sum[i-1])*(sum[N] - (sum[r-1] - sum[i-1])),ans);
        }
        printf("%I64d
",ans);

    }
    return 0;
}

1010 Just do it

智商可能也许大概我也不愿意承认，就是被碾压了。

分析了一下原因 可能是因为思路不够开阔，还有就是学弟呼呼过，影响了心态。

#include <cstdio>

const int N = 200000;

int a[N];

int main()
{
    int T;
    scanf("%d", &T);
    while (T --) {
        int n, m;
        scanf("%d%d", &n, &m);
        for (int i = 0; i < n; ++ i) {
            scanf("%d", a + i);
        }
        for (int k = 0; 1 << k <= m; ++ k) {
            if (m >> k & 1) {
                for (int i = 1 << k; i < n; ++ i) {
                    a[i] ^= a[i - (1 << k)];
                }
            }
        }
        for (int i = 0; i < n; ++ i) {
            printf("%d%c", a[i], " 
"[i == n - 1]);
        }
    }
}

1011 Kolakoski

直接递推。

#include <bits/stdc++.h>
const long long mod = 1e9+7;
const double ex = 1e-10;
#define inf 0x3f3f3f3f
using namespace std;
int a[21234567];
void init()
{
    int cnt1 = 1;
    int cnt2 = 1;
    while (cnt1 <= 10000000)
    {
        a[++cnt1] = (a[cnt1-1]==1?2:1);
        if (a[cnt2+1] == 2) a[++cnt1] = a[cnt1-1];
        cnt2++;
    }
}
int main()
{
    int N;

    a[1] =1;
    init();
    cin >> N;
    while (N--)
    {
        int i;
        cin >> i;
        cout << a[i]<<endl;
    }
    return 0;
}