commit

Author: 王俊超

.idea/modules.xml

@@ -0,0 +1,42 @@
+/**
+ * @author: wangjunchao(王俊超)
+ * @time: 2018-09-28 15:23
+ **/
+public class Solution {
+    public String multiply(String num1, String num2) {
+        int m = num1.length(), n = num2.length();
+        int[] pos = new int[m + n];
+
+        int mul;
+        int index;
+        int temp;
+        for (int i = m - 1; i >= 0; i--) {
+            for (int j = n - 1; j >= 0; j--) {
+                // 求积
+                mul = (num1.charAt(i) - '0') * (num2.charAt(j) - '0');
+                // 积的最低位所在的位置
+                index = i + j + 1;
+
+                // 最低低求和
+                pos[index] += mul;
+
+                // 做进位处理
+                while (pos[index] > 9) {
+                    temp = pos[index];
+                    pos[index] = temp % 10;
+                    --index;
+                    pos[index] += temp / 10;
+                }
+
+            }
+        }
+
+        StringBuilder sb = new StringBuilder();
+        for (int p : pos) {
+            if (!(sb.length() == 0 && p == 0)) {
+                sb.append(p);
+            }
+        }
+        return sb.length() == 0 ? "0" : sb.toString();
+    }
+}