hihoCoder 1249 Xiongnu's Land（二分）

题目链接：hihoCoder 1249 Xiongnu’s Land

代码

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

using namespace std;
typedef long long ll;
const int maxn = 10005;

int N, R, L[maxn], T[maxn], W[maxn], H[maxn];
ll S;

ll get(int x) {
    ll ret = 0;
    for (int i = 0; i < N; i++)
        ret += 1LL * H[i] * max(min(W[i], x - L[i]), 0);
    return ret;
}

int solve () {
    int l = 0, r = R + 1;
    while (l < r) {
        int mid = (l + r) >> 1;
        ll tmp = get(mid);
        if (tmp >= S - tmp) r = mid;
        else l = mid + 1;
    }

    ll ans = get(r);
    l = 0, r = R + 1;
    while (l < r) {
        int mid = (l + r) >> 1;
        if (get(mid) > ans) r = mid;
        else l = mid + 1;
    }
    return l - 1;
}

int main () {
    int cas;
    scanf("%d", &cas);
    while (cas--) {
        S = 0;
        scanf("%d%d", &R, &N);
        for (int i = 0; i < N; i++) {
            scanf("%d%d%d%d", &L[i], &T[i], &W[i], &H[i]);
            S += 1LL * W[i] * H[i];
        }
        printf("%d\n", solve());
    }
    return 0;
}