【Miscalculation UVALive - 6833 】【模拟】

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
using namespace std;
typedef long long LL;
const int maxn = 1000000;
char s[maxn];
int digit[maxn], sum;
int main()
{
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    while(scanf("%s", s) != EOF)
    {
        scanf("%d", &sum);
        int len = strlen(s);
        memset(digit, 0, sizeof(digit));
        int s1 = 0, s2 = 0;
        s1 = int(s[0]-'0');
        for(int i = 1; i < len; )
        {
            if(s[i] == '+')
                s1 += int(s[i+1]-'0');
            else if(s[i] == '*')
                s1 *= int(s[i+1]-'0');
            i += 2;
        }
        
        for(int i = 0; i < len; i = i + 2)
            digit[i] = int(s[i] - '0');     //将数字存储在一个int数组中
        for(int i = 0; i < len; i++)
        {
            if(s[i] == '*')
            {
                digit[i+1] *= digit[i-1];       //后一位乘以前一位，然后赋值给后一位
                digit[i-1] = 0;         //将前一位整成0
            }
            else
                continue;
        }
        for(int i = 0; i < len; i++)
            s2 += digit[i];             //都加起来就可以了
        if(s1 == sum && s2 == sum)
            printf("U");
        else if(s1 == sum)
            printf("L");
        else if(s2 == sum)
            printf("M");
        else 
            printf("I");
        printf("\n");
    }
    
}