Poj百练 2711:合唱队形 （分类：动态规划）

//合唱队形
#include <iostream>
#include<cstdio>
using namespace std;

int N;

int main()
{
    scanf("%d",&N);
    int h[N+5];
    for(int i = 1; i<= N; i++)
        scanf("%d",&h[i]);

    //先从左到右求最长上升子序列
    int dp1[N+5] = {0, 1};
    for(int i = 2; i<= N; i++){
        int tmp = 0;
        for(int j = 1; j < i; j++)
            if(dp1[j] > tmp && h[i] > h[j])
                tmp = dp1[j];
        dp1[i] = tmp + 1;
    }
    //再从右到左求最长上升子序列
    int dp2[N+5];
    dp2[N] = 1;
    for(int i = N-1; i >= 1; i--){
        int tmp = 0;
        for(int j = N; j > i; j--)
            if(dp2[j] > tmp && h[i] > h[j])
                tmp = dp2[j];
        dp2[i] = tmp + 1;
    }

    //找出dp1和dp2的最大和
    int sum = 0, ans;
    for(int i = 1; i <= N; i++){
        if(dp1[i] + dp2[i] > sum)
            sum = dp1[i] + dp2[i];
    }
    ans = N-sum;
    printf("%d",ans+1);
    return 0;
}