PATA1007题解

动态规划题

注意全为负数的情形，输出为0 序列第一个值 序列最后一个值；

注意序列由负数和0组成时，输出为0 0 0；

//
//  main.cpp
//  PATA1007
//
//  Created by Phoenix on 2018/1/31.
//  Copyright © 2018年 Phoenix. All rights reserved.
//

#include <iostream>
#include <cstdio>
const int maxn = 10010;
int num[maxn];
bool flag = false;
int main(int argc, const char * argv[]) {
    int n;
    scanf("%d", &n);
    for(int i = 0; i < n; i++) {
        scanf("%d", &num[i]);
    }
    int start = -1, begin = 0, end = -1, MAX = 0,sum = 0;
    for(int i = 0; i < n; i++) {
        if(num[i] == 0) flag = true;
        if(num[i] > 0){
            sum += num[i];
            if(sum > MAX) {
                MAX = sum;
                end = num[i];
                start = num[begin];
            }
        }else if(num[i] <= 0 && num[i] + sum >= 0) {
            sum += num[i];
        }else{
            sum = 0;
            begin = i + 1;
        }
    }
    if(MAX >0){
        printf("%d %d %d", MAX, start, end);
    }else{
        if(flag == true) printf("0 0 0\n");
        else printf("0 %d %d", num[0], num[n - 1]);
    }
    return 0;
}