// 大数乘法,顺位模拟, 注意i和j位乘积结果放在了i + j - 1中,然后从后往前依次处理进位
class Solution {
public String multiply(String num1, String num2){
if (num1 == "" || num2 == "") return "";
int n = num1.length();
int m = num2.length();
int[] value = new int[n + m];
Arrays.fill(value, 0);
for (int i = n - 1; i >= 0; i--){
for (int j = m - 1; j >= 0; j--){
value[i + j + 1] += (num1.charAt(i) - '0') * (num2.charAt(j) - '0');
// System.out.println(Arrays.toString(value));
}
}
int c = 0;
for (int i = m + n - 1; i >= 0; i--){
value[i] += c;
c = value[i] / 10;
value[i] %= 10;
}
// System.out.println(Arrays.toString(value));
int index = 0;
StringBuffer s = new StringBuffer("");
while(value[index] == 0 && index < m + n - 1){
index++;
}
for (int i = index; i < m + n; i ++){
s.append(value[i]);
}
return s.toString();
}
}
LeetCode43 字符串相乘 大数乘法
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转载自blog.csdn.net/TIMELIMITE/article/details/89928989
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