标题：2008武汉大学软件文化节算法设计大赛D题
出处：Felix021
时间：Sun, 04 May 2008 18:03:57 +0000
作者：felix021
地址：https://www.felix021.com/blog/read.php?903

内容：
2008武汉大学软件文化节算法设计大赛D题Felix的代码. 超时,需要打表- -||

程序如下

#include <iostream>
using namespace std;

char exp[1000], temp[10];
int n, count1;

int eval(char *exp){
    char str[1000], t;
    int i, j, sum, temp;
    char op = 0;
    for(i = 0, j = 0; exp[i] != 0; i++){
        if(exp[i] == '.' || exp[i] == ' ')continue;
        str[j++] = exp[i];
    }
    str[j] = 0;
    sum = 0;
    i = 0;
    while(str[i] != 0){
        if(str[i] == '+' || str[i] == '-'){
            op = str[i];
            i++;
        }else{
            temp = atoi(str + i);
            if(op == 0){
                sum = temp;
            }else if(op == '-'){
                sum -= temp;
            }else if(op == '+'){
                sum += temp;
            }
            while(true){
                if(str[i] == 0 || str[i] == '+' || str[i] == '-')break;
                i++;
            }
        }
    }
    return sum;
}

void go1(int i, int rear){
    int bits = i < 10 ? 1 : 2;
    if(i < n){
        sprintf(exp + rear, "%d + ", i);
        go1(i + 1, rear + bits + 3);
        sprintf(exp + rear, "%d - ", i);
        go1(i + 1, rear + bits + 3);
        sprintf(exp + rear, "%d . ", i);
        go1(i + 1, rear + bits + 3);
    }else if(i == n){
        sprintf(exp + rear, "%d", i);
        go1(i + 1, rear + bits);
    }else{
        if(eval(exp) == 0){
            count1 ++;
            if(count1 <= 20)
                cout << exp << endl;
        }
    }
}

int main(){
    int t;
    cin >> t;
    while(t--){
        count1 = 0;
        cin >> n;
        go1(1, 0);
        cout << count1 << endl;
    }
    return 0;
}



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