uva 11078 单调队列

用一个premin记录之前的最小值

AC代码如下：

#include <iostream>#include <cstring>#include <cstdio>#include <algorithm>using namespace std;int num[100100], N;int premin;int main(){    int T, ans;    scanf( "%d", &T );    while( T-- ){        scanf( "%d", &N );        for( int i = N - 1; i >= 0; i-- ){            scanf( "%d", &num[i] );        }        premin = num[0];        ans = -1000000000;        for( int i = 1; i < N; i++ ){            ans = max( ans, num[i] - premin );            premin = min( premin, num[i] );        }        printf( "%d\n", ans );    }    return 0;}