15. 三数之和

test006.cpp

@@ -0,0 +1,28 @@
+class Solution {
+public:
+    vector<vector<int>> threeSum(vector<int>& nums) {
+        // Ö÷ÒªÎÊÌ⻹ÊÇÈ¥Öظ´
+        int n = nums.size();
+        sort(nums.begin(), nums.end());
+        vector<vector<int>> ret;
+        int preid = -1;
+        for(int i = 0; i < n; i++){
+            if(preid != -1 && nums[i] == nums[preid]) continue;
+            int l = i + 1, r = n - 1;
+            while(l < r){
+                int sum = nums[i] + nums[l] + nums[r];
+                if(sum == 0){
+                    ret.push_back({nums[l], nums[r], nums[i]});
+                    int tmp = nums[l];
+                    while(l < r && nums[l] == tmp) l++;
+                    preid = i;
+                }else if(sum > 0){
+                    r--;
+                }else{
+                    l++;
+                }
+            }
+        }
+        return ret;
+    }
+};