codeforces 250 div2 A B C D

标签：acm   codeforces   

A. 模拟

#include <bits/stdc++.h>

using namespace std;
#define LL long long
#define INF 0x3f3f3f3f
#define maxn 100 + 10

char s[4][maxn];
int len[4];

int main()
{
    int t1, t2;
    int Min = INF, Max = -INF;
    for(int i = 0; i < 4; i++)
    {
        scanf("%s", s[i]);
        len[i] = strlen(s[i]) - 2;
        //cout<<len[i]<<endl;
        if(Max < len[i])
        {
            Max = len[i];
            t1 = i;
        }
         if(Min > len[i])
        {
            Min = len[i];
            t2 = i;
        }
    }

    int t = 0;
    int ans;
    int i ;
    for(i = 0; i < 4; i++)
    {
        if(i != t1 && Max < 2 * len[i])
        {
            break;
        }
    }
    if(i == 4)
    {
        t++;
        ans = t1;
    }

    for(i = 0; i < 4; i++)
    {
        if(i != t2 && 2 * Min > len[i])
        break;
    }
    if(i == 4)
    {
        t++;
        ans = t2;
    }
    if(t == 2 || t == 0)
    printf("C\n");
    else printf("%c\n", 'A' + ans);
    return 0;
}


/*

A._
B.__
C.____
D.________


*/

#include <bits/stdc++.h>

using namespace std;

int lowbit(int x)
{
    return x & ( -x);
}

int n, m;
int a[100005];
int cnt = 0;

int main()
{
    cin>>n>>m;
    for(int i = m; i >= 1; i--)
    {
        if(lowbit(i) <= n)
        {
            n -= lowbit(i);
            a[cnt++] = i;
        }
        if(n == 0) break;
    }
    if(n != 0) printf("-1\n");
    else
    {
        cout<<cnt<<endl;
        for(int i = 0; i < cnt; i++)
    {
        i == cnt - 1 ? printf("%d\n", a[i]) : printf("%d ", a[i]);
    }
    }
    return 0;
}

#include <bits/stdc++.h>

using namespace std;
#define LL long long
#define INF 0x3f3f3f3f
#define maxn 100000 + 10

int v[maxn];
int n, m;

int main()
{
    cin>>n>>m;
    for(int i = 1; i <= n ; i++)
    scanf("%d", v + i);

    long long ans = 0;
    for(int i = 0; i < m; i++)
    {
        int uu, vv;
        scanf("%d%d", &uu, &vv);
        ans += min(v[uu], v[vv]);
    }
    printf("%I64d\n", ans);
    return 0;
}

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
#define N 100000 + 10

struct Edge
{
    int u, v, w;
}e[N];

int n, m;
int w[N];
int f[N], cnt[N];
double ans = 0;

int cmp(Edge a, Edge b)
{
    return a.w > b.w;
}

void mekeset()
{
    for(int i = 1; i <= n; i++)
    {
        f[i] = i;
        cnt[i] = 1;
    }
}

int Find(int x)
{
    return x == f[x] ? x : f[x] = Find(f[x]);
}

int Union(int i, int x, int y)
{
    int xx = Find(x);
    int yy = Find(y);
    if(xx != yy)
    {
       ans += (double)e[i].w * cnt[xx] * cnt[yy];
       cnt[xx] += cnt[yy];
       f[yy] = xx;
    }
}

int main()
{
    scanf("%d%d", &n, &m);
    for(int i = 1; i <= n; i++)
    {
        scanf("%d", w + i);
    }
    for(int i = 0; i < m; i++)
    {
        scanf("%d%d", &e[i].u, &e[i].v);
        e[i].w = min(w[e[i].u], w[e[i].v]);
    }
    sort(e, e + m, cmp);

    mekeset();
    for(int i = 0; i < m; i++)
    {
        Union(i, e[i].u, e[i].v);
    }
    ans = ans * 2 / ((double)n *(n - 1));
    printf("%.6lf\n", ans);
    return  0;
}

codeforces 250 div2 A B C D

标签：acm   codeforces   

原文地址：http://blog.csdn.net/dojintian/article/details/47703527