codeforces - 18C - Stripe（练习）

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Once Bob took a paper stripe of n squares (the height of the stripe is 1 square). In each square he wrote an integer number, possibly negative. He became interested in how many ways exist to cut this stripe into two pieces so that the sum of numbers from one piece is equal to the sum of numbers from the other piece, and each piece contains positive integer amount of squares. Would you help Bob solve this problem?

Input

The first input line contains integer n (1 ≤ n ≤ 105) — amount of squares in the stripe. The second line contains n space-separated numbers — they are the numbers written in the squares of the stripe. These numbers are integer and do not exceed 10000 in absolute value.

Output

Output the amount of ways to cut the stripe into two non-empty pieces so that the sum of numbers from one piece is equal to the sum of numbers from the other piece. Don't forget that it's allowed to cut the stripe along the squares' borders only.

Sample test(s)
input
91 5 -6 7 9 -16 0 -2 2
output
3
input
31 1 1
output
0
input
20 0
output
1

这道题目= =题意跟数据完全不是一个意思= =

按照数据来说，题意就是，给出N个数，切成两部分且保证每部分至少有一个数，并使两部分的和相等。

一开始根据题意不停的wa wa wa = = 直到看了cf 的数据才明白题目描述有问题= =

#include <iostream>#include <algorithm>#include <cstdio>#include <stdlib.h>#include <cmath>#include <cstring>#include <cstdlib>#include <iostream>#include <set>using namespace std;int a[100005];int main(){  int n;  while(scanf("%d", &n) != EOF){    int sum = 0;    for(int i = 0; i < n; i++){      scanf("%d", &a[i]);      sum += a[i];    }    int ans = 0;    int sum2 = a[0];    for(int i = 1; i < n; i++){      if((sum2 * 2 == sum)){        ans++;      }      sum2 += a[i];    }    printf("%d\n", ans);  }  return 0;}

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