3sum 풀이 추가

Author: junzero741

3sum/junzero741.ts

@@ -0,0 +1,45 @@
+// TC: O(n^2)
+// SC: O(logn)
+function threeSum(nums: number[]): number[][] {
+    
+    nums.sort((a,b) => a-b);
+    const result: number[][] = []
+
+    for(let i = 0 ; i < nums.length; i++) {
+        let left = i+1;
+        let right = nums.length-1;
+
+        while(left < right) {
+           if(i > 0 && nums[i] === nums[i-1]) {
+                break;
+           }
+
+           const sum = nums[i] + nums[left] + nums[right];
+           if(sum > 0) {
+                right--;
+                continue;
+           }
+           if(sum < 0) {
+                left++;
+                continue;
+           }
+           if(sum === 0) {
+                const triplet: number[] = [nums[i], nums[left], nums[right]];
+                result.push(triplet);
+
+                while(left < right && nums[left] === nums[left+1]) {
+                    left++;
+                }
+                while(left < right && nums[right] === nums[right-1]) {
+                    right--;
+                }
+
+                left++;
+                right--;
+           }
+        }
+        
+    }
+
+    return result;
+};