Merge pull request #3 from kwu130/remove-warning-info

refactor(cpp): improve type safety and loop conditions

Author: kwu130

include/common.h

@@ -22,7 +22,7 @@ ListNode* build(const std::vector<int>& vec) {
     if (vec.empty()) return nullptr;
     ListNode* head = new ListNode(vec[0]);
     ListNode* cur = head;
-    for (int i = 1; i < vec.size(); i++) {
+    for (size_t i = 1; i < vec.size(); i++) {
         cur->next = new ListNode(vec[i]);
         cur = cur->next;
     }

src/1-twoSum.cpp

@@ -10,7 +10,7 @@ class Solution {
 public:
     vector<int> twoSum(vector<int>& nums, int target) {
         unordered_map<int, int> hash;
-        for (int i = 0; i < nums.size(); i++) {
+        for (int i = 0; i < static_cast<int>(nums.size()); i++) {
             if (hash.contains(target - nums[i])) {
                 return {hash[target - nums[i]], i};
             }

src/13-romanToInt.cpp

@@ -20,8 +20,9 @@ class Solution {
         m['M'] = 1000;
 
         int res = 0;
-        for (int i = 0; i < s.size(); i++) {
-            if (i < s.size() - 1 && m[s[i]] < m[s[i + 1]]) {
+        const int n = static_cast<int>(s.size());
+        for (int i = 0; i < n; i++) {
+            if (i < n - 1 && m[s[i]] < m[s[i + 1]]) {
                 res -= m[s[i]];
             } else {
                 res += m[s[i]];

src/14-longestCommonPrefix.cpp

@@ -9,9 +9,10 @@ using namespace std;
 class Solution {
 public:
     string longestCommonPrefix(vector<string>& strs) {
-        for (int i = 0; i < strs[0].size(); i++) {
+        const int n = static_cast<int>(strs[0].size());
+        for (int i = 0; i < n; i++) {
             for (const auto& str : strs) {
-                if (i >= str.size() || str[i] != strs[0][i]) {
+                if (i >= n || str[i] != strs[0][i]) {
                     return strs[0].substr(0, i);
                 }
             }

src/15-threeSum.cpp

@@ -14,11 +14,12 @@ class Solution {
         }
         vector<vector<int>> res;
         ranges::sort(nums);
-        for (int i = 0; i < nums.size() - 2; i++) {
+        const int n = static_cast<int>(nums.size());
+        for (int i = 0; i < n - 2; i++) {
             if (i > 0 && nums[i] == nums[i - 1]) {
                 continue;
             }
-            int left = i + 1, right = nums.size() - 1;
+            int left = i + 1, right = n - 1;
             while (left < right) {
                 int sum = nums[i] + nums[left] + nums[right];
                 if (sum == 0) {

src/16-threeSumClosest.cpp

@@ -11,11 +11,12 @@ class Solution {
     int threeSumClosest(vector<int>& nums, int target) {
         int res = nums[0] + nums[1] + nums[2];
         ranges::sort(nums);
-        for (int i = 0; i < nums.size() - 2; i++) {
+        const int n = static_cast<int>(nums.size());
+        for (int i = 0; i < n - 2; i++) {
             if (i > 0 && nums[i] == nums[i - 1]) {
                 continue;
             }
-            int left = i + 1, right = nums.size() - 1;
+            int left = i + 1, right = n - 1;
             while (left < right) {
                 int sum = nums[i] + nums[left] + nums[right];
                 if (sum == target) {

src/17-letterCombinations.cpp

@@ -21,7 +21,7 @@ class Solution {
     const vector<string> m{"", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
 
     void dfs(const string& digits, int index, string&& path, vector<string>& res) {
-        if (index == digits.size()) {
+        if (index == static_cast<int>(digits.size())) {
             res.push_back(path);
             return;
         }

src/18-fourSum.cpp

@@ -16,10 +16,11 @@ class Solution {
 
 private:
     vector<vector<int>> kSum(vector<int>& nums, int k, int start, long target) {
-        if (nums.size() < k || k < 2) return {};
+        const int n = static_cast<int>(nums.size());
+        if (n < k || k < 2) return {};
         vector<vector<int>> res;
         if (k == 2) {
-            int left = start, right = nums.size() - 1;
+            int left = start, right = n - 1;
             while (left < right) {
                 long sum = nums[left] + nums[right];
                 if (sum == target) {
@@ -33,13 +34,13 @@ class Solution {
                 }
             }
         } else {
-            for (int i = start; i < nums.size(); i++) {
+            for (int i = start; i < n; i++) {
                 auto sub = kSum(nums, k - 1, i + 1, target - nums[i]);
                 for (auto& v : sub) {
                     v.push_back(nums[i]);
                     res.push_back(v);
                 }
-                while (i < nums.size() - 1 && nums[i] == nums[i + 1]) i++;
+                while (i < n - 1 && nums[i] == nums[i + 1]) i++;
             }
         }
 

src/26-removeDuplicates.cpp

@@ -11,7 +11,7 @@ class Solution {
     int removeDuplicates(vector<int>& nums) {
         if (nums.empty()) return 0;
         int res = 0;
-        for (int i = 1; i < nums.size(); i++) {
+        for (int i = 1; i < static_cast<int>(nums.size()); i++) {
             if (nums[res] != nums[i]) {
                 nums[++res] = nums[i];
             }
@@ -24,12 +24,12 @@ void test() {
     Solution s;
     vector<int> nums = {1, 1, 2};
     vector<int> expected = {1, 2};
-    assert(s.removeDuplicates(nums) == expected.size());
+    assert(s.removeDuplicates(nums) == static_cast<int>(expected.size()));
     assert(vector<int>(nums.begin(), nums.begin() + expected.size()) == expected);
 
     nums = {0, 0, 1, 1, 1, 2, 2, 3, 3, 4};
     expected = {0, 1, 2, 3, 4};
-    assert(s.removeDuplicates(nums) == expected.size());
+    assert(s.removeDuplicates(nums) == static_cast<int>(expected.size()));
     assert(vector<int>(nums.begin(), nums.begin() + expected.size()) == expected);
 }
 

src/27-removeElement.cpp

@@ -11,7 +11,7 @@ class Solution {
     int removeElement(vector<int>& nums, int val) {
         if (nums.empty()) return 0;
         int res = -1;
-        for (int i = 0; i < nums.size(); i++) {
+        for (int i = 0; i < static_cast<int>(nums.size()); i++) {
             if (nums[i] != val) {
                 nums[++res] = nums[i];
             }
@@ -24,17 +24,17 @@ void test() {
     Solution s;
     vector<int> nums = {3, 2, 2, 3};
     vector<int> expected = {2, 2};
-    assert(s.removeElement(nums, 3) == expected.size());
+    assert(s.removeElement(nums, 3) == static_cast<int>(expected.size()));
     assert(vector<int>(nums.begin(), nums.begin() + expected.size()) == expected);
 
     nums = {0, 1, 2, 2, 3, 0, 4, 2};
     expected = {0, 1, 3, 0, 4};
-    assert(s.removeElement(nums, 2) == expected.size());
+    assert(s.removeElement(nums, 2) == static_cast<int>(expected.size()));
     assert(vector<int>(nums.begin(), nums.begin() + expected.size()) == expected);
 
     nums = {};
     expected = {};
-    assert(s.removeElement(nums, 1) == expected.size());
+    assert(s.removeElement(nums, 1) == static_cast<int>(expected.size()));
     assert(vector<int>(nums.begin(), nums.begin() + expected.size()) == expected);
 }