hdu 1176免费馅饼（记忆化搜索）

题目链接 http://acm.hdu.edu.cn/showproblem.php?pid=1176

题意不解释了

简单的记忆化搜索可以拿来练练手，注意要从pos = 5 开始搜索

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <cmath>
using namespace std;
const int M = 1e5 + 10;
int dp[15][M] , t2[M][12];
int dfs(int pos , int count) {
    if(count == 0) {
        if(pos == 6) {
            return 0;
        }
        else {
            return -1;
        }
    }
    if(dp[pos][count] != -1)
        return dp[pos][count];
    int sum = 0;
    if(pos == 1) {
        sum += max(dfs(pos + 1 , count - 1) , dfs(pos , count - 1));
    }
    else if(pos == 11) {
        sum += max(dfs(pos - 1 , count - 1) , dfs(pos , count - 1));
    }
    else {
        sum += max(max(dfs(pos - 1 , count - 1) , dfs(pos + 1 , count - 1)) , dfs(pos , count - 1));
    }
    if(sum != -1) {
        sum += t2[count][pos];
        dp[pos][count] = sum;
    }
    return sum;
}
int main() {
    int n;
    while(scanf("%d" , &n) != EOF) {
        if(n == 0)
            break;
        memset(t2 , 0 , sizeof(t2));
        int T = 0;
        for(int i = 0 ; i < n ; i++) {
            int x , y;
            scanf("%d%d" , &x , &y);
            t2[y][x + 1]++;
            T = max(T , y);
        }
        memset(dp , -1 , sizeof(dp));
        int MAX = 0;
        for(int i = 1 ; i <= 11 ; i++) {
            MAX = max(MAX , dfs(i , T));
        }
        printf("%d
" , MAX);
    }
    return 0;
}