Yet Another Median Task Gym

来源：互联网发布：瑞尔森大学怎么样知乎编辑：程序博客网时间：2024/06/05 03:27

数据挺水

直接排序复杂度有点高，可以二分中位数

#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <cmath>#include <set>#include <map>#include <stack>#include <queue>#include <ctype.h>#include <vector>#include <algorithm>#include <time.h>// cout << "  ===  " << endl;using namespace std;typedef long long ll;const int maxn = 800 + 7;const ll INF = 0x3f3f3f3f3f3f3f3f, mod = 1e9+7;int n, m, t;int a[maxn][maxn];void init() {    scanf("%d %d", &n, &m);    for(int i = 1; i <= n; ++i) {        for(int j = 1; j <= n; ++j)            scanf("%d", &a[i][j]);    }}void solve() {    int x1, x2, y1, y2;    for(int i = 0; i < m; ++i) {        scanf("%d %d %d %d", &x1, &y1, &x2, &y2);        int cnt = (x2-x1+1)*(y2-y1+1);        t = (cnt+1)/2 - 1;               ll l_ = INF, r_ = -INF;        int mid, ans;        for(int i = x1; i <= x2; ++i) {            for(int j = y1; j <= y2; ++j)                l_ = min(l_, (ll)a[i][j]), r_ = max(r_, (ll)a[i][j]);        }        l_ = (int)l_, r_ = (int)r_;        while(l_ <= r_) {                         int num = 0;            mid = (l_ + r_) / 2;            for(int i = x1; i <= x2; ++i) {                for(int j = y1; j <= y2; ++j)                    if(a[i][j] < mid) num++;            }            if(num <= t) {                l_ = mid+1;                ans = mid;            }            else if(num > t) r_ = mid-1;        }        printf("%d\n", ans);    }}int main() {    init();    solve();    return 0;}

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