s0016

src/s0016_3sum_closest.cpp

@@ -0,0 +1,27 @@
+#include "s0016_3sum_closest.hpp"
+
+// 和上一道一样，排序 + 双指针
+
+int Solution::threeSumClosest(vector<int>& nums, int target) {
+  int sum = nums[0] + nums[1] + nums[2];
+  int len = nums.size();
+  sort(nums.begin(), nums.end());
+  for (int i{1}; i < len - 1; i++) {
+    for (int j{0}, k = len - 1; j != k && i != j && i != k;) {
+      if (nums[i] + nums[j] + nums[k] > target) {
+        if (abs(nums[i] + nums[j] + nums[k] - target) < abs(sum - target)) {
+          sum = nums[i] + nums[j] + nums[k];
+        }
+        k--;
+      } else if (nums[i] + nums[j] + nums[k] < target) {
+        if (abs(nums[i] + nums[j] + nums[k] - target) < abs(sum - target)) {
+          sum = nums[i] + nums[j] + nums[k];
+        }
+        j++;
+      } else {
+        return nums[i] + nums[j] + nums[k];
+      }
+    }
+  }
+  return sum;
+}