373

Author: yubinbai

Diff for: README.md

@@ -3,6 +3,7 @@ Leetcode solutions in C++, Java, Python
 
 |#|Title|Solution|Difficulty|
 |---|-----|--------|----------|
+|373|[Find K Pairs with Smallest Sums](./src/find_k_pairs_with_smallest_sums)|[C++](./src/find_k_pairs_with_smallest_sums)|Medium|
 |372|[Super Pow](./src/super_pow)|[C++](./src/super_pow)|Medium|
 |371|[Sum of Two Integers](./src/sum_of_two_integers)|[C++](./src/sum_of_two_integers)|Easy|
 |370|[Range Addition](./src/range_addition)|[C++](./src/range_addition)|Medium|

Diff for: src/find_k_pairs_with_smallest_sums/Makefile

@@ -0,0 +1,6 @@
+all:
+	clang++ main.cpp -o main.o -std=c++11
+
+run:
+	clang++ main.cpp -o main.o -std=c++11
+	./main.o

Diff for: src/find_k_pairs_with_smallest_sums/README.md

@@ -0,0 +1,16 @@
+Problem
+===
+
+You are given two integer arrays nums1 and nums2 sorted in ascending order and an integer k.
+
+Define a pair (u,v) which consists of one element from the first array and one element from the second array.
+
+Find the k pairs (u1,v1),(u2,v2) ...(uk,vk) with the smallest sums.
+
+
+Solution
+===
+
+Find all possible pairs and sort
+
+O(k^2 logk)

Diff for: src/find_k_pairs_with_smallest_sums/main.cpp

@@ -0,0 +1,76 @@
+#include <algorithm>
+#include <cstdlib>
+#include <iostream>
+#include <map>
+#include <queue>
+#include <set>
+#include <sstream>
+#include <stack>
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+using namespace std;
+
+bool comp_pairs (pair<int, int> p, pair<int, int> q) {
+  return (p.first + p.second < q.first + q.second);
+}
+
+class Solution {
+public:
+  vector<pair<int, int>> kSmallestPairs(vector<int>& nums1, vector<int>& nums2, int k) {
+    vector<pair<int, int>> result;
+    for (int i = 0; i < k && i < nums1.size(); i++) {
+      for (int j = 0; j < k - i && j < nums2.size(); j++) {
+        result.push_back(make_pair(nums1[i], nums2[j]));
+      }
+    } 
+    sort(result.begin(), result.end(), comp_pairs);
+    if (result.size() < k) {
+      return result;
+    }
+    vector<pair<int, int>> ret(result.begin(), result.begin() + k);
+    return ret;
+  }
+};
+
+int main() {
+  Solution sol;
+  vector<int> a, b;
+  int k;
+
+  a = {1, 7, 11};
+  b = {2, 4, 6};
+  k = 3;
+  for (auto p: sol.kSmallestPairs(a, b, k)) {
+    cout << p.first << ", " << p.second << endl;
+  }
+  cout << endl;
+
+  a = {1, 1, 2};
+  b = {1, 2, 3};
+  k = 2;
+  for (auto p: sol.kSmallestPairs(a, b, k)) {
+    cout << p.first << ", " << p.second << endl;
+  }
+  cout << endl;
+
+  a = {1, 2};
+  b = {3};
+  k = 2;
+  for (auto p: sol.kSmallestPairs(a, b, k)) {
+    cout << p.first << ", " << p.second << endl;
+  }
+  cout << endl;
+
+  a = {};
+  b = {};
+  k = 5;
+  for (auto p: sol.kSmallestPairs(a, b, k)) {
+    cout << p.first << ", " << p.second << endl;
+  }
+  cout << endl;
+
+  return 0;
+}