Merge pull request #1800 from CodingTestStudy2/염혜정

[염혜정] Day12

Author: github-actions[bot]

leetcode3/염혜정/476. Number Complement.java

@@ -0,0 +1,33 @@
+// 10진수 -> 2진수
+// 1과 0을 서로 바꿈
+// 2진수 -> 10진수
+
+
+class Solution {
+    public int findComplement(int num) {
+        StringBuilder sb = new StringBuilder();
+        while (num>0) {
+            int bit = num%2;
+            // 0과 1을 체인지
+            if (bit == 0) sb.append(1);
+            else sb.append(0);
+            num /= 2;
+        }
+
+        String ten = sb.toString();
+        int result = ten.charAt(0) - '0';
+        if (ten.length() == 1) return result;
+
+        for (int i = 1; i<ten.length(); i++) {
+            int digit = ten.charAt(i) - '0';
+            if (digit == 0) continue;
+            int pow = 1;
+            for (int cnt = 0; cnt<i; cnt++) {
+                pow *= 2;
+            }
+            result += pow;
+        }
+
+        return result;
+    }
+}