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-rw-r--r--integer_replacement.c31
-rw-r--r--integer_replacement.py33
2 files changed, 64 insertions, 0 deletions
diff --git a/integer_replacement.c b/integer_replacement.c
new file mode 100644
index 0000000..8a3fdb8
--- /dev/null
+++ b/integer_replacement.c
@@ -0,0 +1,31 @@
+// 397. Integer Replacement
+#include "leetcode.h"
+
+/*
+ * given a positive integer 'n', you can apply one of the following operations:
+ * if 'n' is even, replace 'n' witn 'n / 2'. if 'n' is odd, replace 'n' with
+ * either 'n + 1' or 'n - 1'. return the minimum number of operations needed for
+ * 'n' to become 1
+ */
+
+int integerReplacement(int n) {
+ int ans = 0;
+ while (n > 1) {
+ if (n == 3)
+ return ans + 2;
+ else if (!(n & 1))
+ n = (n >> 1) & 0x7FFFFFFF;
+ else if (!((n + 1) % 4))
+ n++;
+ else
+ n--;
+ ans++;
+ }
+ return ans;
+}
+
+int main() {
+ printf("%d\n", integerReplacement(8)); // expect: 3
+ printf("%d\n", integerReplacement(7)); // expect: 4
+ printf("%d\n", integerReplacement(4)); // expect: 2
+}
diff --git a/integer_replacement.py b/integer_replacement.py
new file mode 100644
index 0000000..8d7dbda
--- /dev/null
+++ b/integer_replacement.py
@@ -0,0 +1,33 @@
+# 397. Integer Replacement
+
+"""
+given a positive integer 'n', you can apply one of the following operations:
+if 'n' is even, replace 'n' witn 'n / 2'. if 'n' is odd, replace 'n' with
+either 'n + 1' or 'n - 1'. return the minimum number of operations needed for
+'n' to become 1
+"""
+
+
+class Solution(object):
+ def integerReplacement(self, n):
+ """
+ :type n: int
+ :rtype: int
+ """
+ ans = 0
+ while n > 1:
+ ans += 1
+ if n % 2 == 0:
+ n //= 2
+ elif n % 4 == 1 or n == 3:
+ n -= 1
+ else:
+ n += 1
+ return ans
+
+
+if __name__ == "__main__":
+ obj = Solution()
+ print(obj.integerReplacement(n=8))
+ print(obj.integerReplacement(n=7))
+ print(obj.integerReplacement(n=4))