题目1498：寻找表达式

最新推荐文章于 2024-03-23 18:50:08 发布

Aden2224

最新推荐文章于 2024-03-23 18:50:08 发布

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分类专栏：九度OJ

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#include <stdio.h>
  
int op[20];
char s[3] = {'+','-',' '};
int n;
void dfs(int layer,int currentSum,int lastOp,int lastSum)
{
    lastSum *= (layer > 9 ? 100 : 10);
    lastSum += layer;
    if(layer == n)
    {
        currentSum += (lastOp) ? (-1 * lastSum) : lastSum;
        if(currentSum == 0)
        {
            printf("1");
            for(int i = 2;i <= n;i++)
                printf("%c%d",s[op[i - 1]],i);
            printf("\n");
        }
        return;
    }
  
    op[layer] = 2;
    dfs(layer + 1,currentSum,lastOp,lastSum);
    currentSum += (lastOp) ? (-1 * lastSum) : lastSum;
    op[layer] = 0;
    dfs(layer + 1,currentSum,0,0);
    op[layer] = 1;
    dfs(layer + 1,currentSum,1,0);
}
  
int main()
{
    while(scanf("%d",&n) != EOF)
    {
        dfs(1,0,0,0);
    }
    return 0;
}
/**************************************************************
    Problem: 1498
    User: cust123
    Language: C++
    Result: Accepted
    Time:90 ms
    Memory:1020 kb
****************************************************************/