int duplicate(vector<int>& numbers) { // write code here map<int, int> m; for (int i = 0; i < numbers.size(); i++) { m[numbers[i]]++; if (m[numbers[i]] > 1) return numbers[i]; } return -1; }是什么意思

arr) {
int n = arr.size();
if (n == 0 || n == 1) {
return -1;
}
sort(arr.begin(), arr.end());
for (int i = 0; i < n - 1; i++) {
if (arr[i] == arr[i+1]) {
return arr[i];
}
}
return -1;
}

// This function takes a vector of integers as input and returns the first duplicate value found in the vector.
// If no duplicate value is found, it returns -1. The function uses a sorting approach to find the duplicate value.
// First, the vector is sorted and then checked for adjacent elements with the same value. If such elements are found,
// the first duplicate value is returned.

相关问题

vector<vector<int>> threeSum(vector<int>& nums) 这句代码什么意思

nums) {
vector<vector<int>> result;
if(nums.size() < 3) return result;

sort(nums.begin(), nums.end()); // sort the array

for(int i=0; i<nums.size()-2; i++) {
if(i == 0 || (i > 0 && nums[i] != nums[i-1])) { // skip duplicate elements

int low = i+1, high = nums.size()-1, sum = 0-nums[i];
while(low < high) {
if(nums[low] + nums[high] == sum) {
result.push_back({nums[i], nums[low], nums[high]});
while(low < high && nums[low] == nums[low+1]) low++; // skip duplicate elements
while(low < high && nums[high] == nums[high-1]) high--; // skip duplicate elements
low++;
high--;
} else if(nums[low] + nums[high] < sum) {
low++;
} else {
high--;
}
}
}
}
return result;
}

vue.runtime.esm.js?2b0e:619 [Vue warn]: Duplicate keys detected: '/addStudent'. This may cause an update error. found in ---> <SidebarItem> at src/layout/components/Sidebar/SidebarItem.vue <ElMenu> at packages/menu/src/menu.vue <ElScrollbar> <Sidebar> at src/layout/components/Sidebar/index.vue <Layout> at src/layout/index.vue <App> at src/App.vue <Root> warn @ vue.runtime.esm.js?2b0e:619 vue.runtime.esm.js?2b0e:619 [Vue warn]: Duplicate keys detected: '/addStudent'. This may cause an update error. found in ---> <SidebarItem> at src/layout/components/Sidebar/SidebarItem.vue <ElMenu> at packages/menu/src/menu.vue <ElScrollbar> <Sidebar> at src/layout/components/Sidebar/index.vue <Layout> at src/layout/index.vue <App> at src/App.vue <Root>

这个警告提示是 Vue 在渲染 DOM 时发现了重复的 key，这可能会导致更新错误。出现这个问题的原因通常是在渲染列表时使用了相同的 key 值，你需要检查你的代码，确保所有的 key 值是唯一的。在你的代码中，这个问题出现在 SidebarItem 组件中，key 值为 '/addStudent' 的元素出现了重复。你可以修改 key 值，或者使用一个动态的 key 值来解决这个问题。