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authorjack <[email protected]>2024-06-14 13:13:15 -0600
committerjack <[email protected]>2024-06-14 13:13:15 -0600
commitd343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch)
tree96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /power_of_four.c
downloadleetcode-d343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa.tar.gz
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+// 342. Power of Four
+#include <stdbool.h>
+#include <stdio.h>
+
+/*
+ * given an integer 'n', return 'true' if it is a power of four, otherwise,
+ * return 'false'. an integer 'n' is a power of four if there exists an integer
+ * 'x' such that 'n == 4^x'
+ */
+
+bool isPowerOfFour(int n) {
+ int ans = 0, pos = 1, ones = 0;
+ while (n) {
+ if (n & 1) { // if 'n' is even...
+ ans++;
+ ones = pos;
+ }
+ n >>= 1; // 'n' / 2
+ pos++;
+ }
+ return ans == 1 && ones & 1;
+}
+
+int main() {
+ printf("%d\n", isPowerOfFour(16)); // expect: 1
+ printf("%d\n", isPowerOfFour(5)); // expect: 0
+ printf("%d\n", isPowerOfFour(1)); // expect: 1
+}