leetcode43：字符串相乘

leetcode43：字符串相乘

解题思路

1. 核心代码（leetcode/牛客可执行）

class Solution {
public:
    string multiply(string num1, string num2) {
        int l1 = num1.length(), l2 = num2.length();
        string res(l1+l2, '0');
        int i, j;
        for(i=l1-1; i>=0; i--){
            for(j=l2-1; j>=0; j--){
                int p1=i+j, p2=i+j+1;
                int mul = (num1[i] -'0') * (num2[j] - '0') + (res[p2] - '0');
                res[p2] = mul % 10 + '0';
                res[p1] = res[p1] - '0' + (mul / 10 + '0');
            }
        }
        int k =0;
        while(k < res.length() && res[k] == '0'){
            k++;
        }
        res = res.substr(k);
        
        return res.length() == 0 ? "0" : res;
    }
};

2. 完整可运行代码

待补充