feat: 50_pow_x_n

50_pow_x_n/main.cpp

@@ -0,0 +1,52 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+   public:
+    double myPow(double x, long long n) {
+        if (x == 0) return 0;
+        if (n == 0) return 1;
+
+        bool isNeg = n < 0;
+        n = abs(n);
+
+        int logn = (int)log2(n);
+
+        vector<double> expTable{x};
+
+        for (int i = 1; i < logn + 1; i++) {
+            expTable.emplace_back(expTable.back() * expTable.back());
+        }
+
+        double result = 1.0;
+        for (int i = 0; i < logn + 1; i++) {
+            if (n & 1) result *= expTable[i];
+            n >>= 1;
+        }
+
+        if (isNeg) result = 1.0 / result;
+
+        return result;
+    }
+};
+
+/*
+
+ 1010
+&0001
+-----
+    0
+
+  101
+& 001
+-----
+    1
+
+x^10
+
+x^8 1
+x^4 0
+x^2 1
+x^1 0
+
+*/