poj 3250 Bad Hair Day 单调栈

来源：互联网发布：linux配置java环境编辑：程序博客网时间：2024/06/06 06:56

题意：n头牛往右看能看到的头顶总数（即身高小于它的）

#include <map>#include <set>#include <queue>#include <stack>#include <vector>#include <string>#include <math.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <iostream>#include <algorithm>using namespace std;#define lson l, mid, rt << 1#define rson mid + 1, r, rt << 1 | 1#define ls rt << 1#define rs rt << 1 | 1#define pi acos(-1.0)#define eps 1e-8#define asd puts("sdfsdfsdfsdfsdfsdf");typedef long long ll;typedef __int64 LL;const int inf = 0x3f3f3f3f;stack<int> s;ll sum;int main(){    int n, h, t;    while( ~scanf("%d", &n) )    {        sum = 0;        scanf("%d", &h);        while( !s.empty() ) s.pop();        s.push( h );        for(int i = 1; i < n; ++i)        {            scanf("%d", &t);            while( !s.empty() && t >= s.top() )                s.pop();            sum += s.size();            s.push(t);        }        printf("%lld\n", sum);    }    return 0;}

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