• <div><p>This implements support for unique indexes, using annotations. <p>Example: <pre><code> php /* * string * * \Property * \Index(unique=true) */ protected \$email; </code></pre> <p>For ...
• We should not check for unique identifier for vendor in latest receipt info. This has caused a critical bug where restoration will always fails. <p>This commit attempts to fixed this issue. <p>Because...
• <div><p>When testing for a unique index on a model, way the title on an article I get this error: <pre><code> LocalJumpError: no block given (yield) </code></pre> <p>This is coming from this line in...
• <div><p>Tests should be added for the fixes merged in #153 </p><p>该提问来源于开源项目：rapidsai/cudf</p></div>
• tool does not check for unique Feature Class names. The tool requires the user to specify three feature class names for the Point, Line and Polygon feature classes, but it does not check if they are ...
• Https schemes </li><li>Fixing documentation to account for changes to clean json when adding new validation rules</li><li>Adding validation rule that ensures we reference a unique resource path within...
• <p>Versioned needs to convert unique indexes to non-unique for its suffixed tables, such as Foo_Live and Foo_versions. Because DataObject accepts string descriptors such as array('UniqIDX' &#...
• <div><p>I don't know if this really is the... Well, it is unique enough for me, maybe an md5 of the text is an alternative as well.</p><p>该提问来源于开源项目：ludovicchabant/PieCrust</p></div>
• </code> filter</a> for plugins to short-circuit the non-performant approach it takes to determining unique post slugs/<code>post_name</code> values. <p>We can take advantage of this filter to fix #44 ...
• <p>Helper for getting unique_index_columns of IC table from a DB, asking for explicit definition if there is more than 1 index and asking for adding unique index if there is none.</p><p>该提问来源于...
• <div><p>该提问来源于开源项目：rust-itertools/itertools</p></div>
• <p>This commit adds the data structure for multi-column unique constraint in create_statement.h. </li><li> <p>This aligns with the current foreign key constraints. It will be needed by the parser team...
• dict((c.name, c) for c in conn_unique_constraints) conn_indexes_by_name = dict((c.name, c) for c in conn_indexes) conn_names = dict( - (c.name, c) + (c.md_name_to_sql_name(autogen_...
• <div><p>This addresses the compiler warning described in #574, which is ... Unit tests for the sugar function <code>unique</code> are also added.</p><p>该提问来源于开源项目：RcppCore/Rcpp</p></div>
• 11, we should probably swap in unique_ptr for the small handful of cases where it is used, and typedef auto_ptr to it for the TR1 case.</p><p>该提问来源于开源项目：alembic/alembic</p></div>
• A hash algorithm takes a piece of text and gives a hash as result. This hash is unique for the given text. If you use the hash function on the same text again, youll get the same hash. But there is n
A hash algorithm takes a piece of text and gives a hash as result. This hash is unique for the given text. If you use the hash function on the same text again, you'll get the same hash. But there is no way to get the given text from the hash. This is great for storing passwords. see more in: http://www.developerfusion.co.uk/show/4601/
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• We should pay attention to the duplicates in this problem. STL offers a way to be unique:  class Solution { public: vector > fourSum(vector &num, int target) { vector > ret; if(num.size() )

Given an array S of n integers, are there elements a, b, c, and d in S such
that a + b + c + d = target? Find all unique quadruplets in the array which gives
the sum of target.
Note:
Elements in a quadruplet (a,b,c,d) must be in non-descending order. (ie, a ≤ b ≤ c ≤ d)The solution set must not contain duplicate quadruplets.    For example, given array S = {1 0 -1 0 -2 2}, and target = 0.

A solution set is:
(-1,  0, 0, 1)
(-2, -1, 1, 2)
(-2,  0, 0, 2)

We should pay attention to the duplicates in this problem. STL offers a way to be unique:

class Solution {
public:
vector<vector<int> > fourSum(vector<int> &num, int target) {
vector<vector<int> > ret;
if(num.size() < 4) return ret;
sort(num.begin(), num.end());
for(int i = 0; i < num.size(); ++i)
for(int j = i + 1; j < num.size(); ++j) {
int left = j + 1;
int right = (int)num.size() - 1;
int sum = 0;
while(left < right){
sum=num[i]+num[j]+num[left]+num[right];
if(target == sum){
ret.push_back(vector<int>(4));
ret.back()[0]=num[i];
ret.back()[1]=num[j];
ret.back()[2]=num[left];
ret.back()[3]=num[right];
++left;
--right;
}
else if(sum > target)
--right;
else
++left;
}
}
vector<vector<int>>:: iterator it = unique(ret.begin(),ret.end());
ret.resize(distance(ret.begin(), it));
return ret;
}
};
The function unique Removes all but the first element from every consecutive group of equivalent elements in the range [first,last).
Here's the example from the cplusplus.com. Vectors could be sorted since we could compare every two vectors.

// unique algorithm example
#include <iostream>     // std::cout
#include <algorithm>    // std::unique, std::distance
#include <vector>       // std::vector

bool myfunction (int i, int j) {
return (i==j);
}

int main () {
int myints[] = {10,20,20,20,30,30,20,20,10};           // 10 20 20 20 30 30 20 20 10
std::vector<int> myvector (myints,myints+9);

// using default comparison:
std::vector<int>::iterator it;
it = std::unique (myvector.begin(), myvector.end());   // 10 20 30 20 10 ?  ?  ?  ?
//                ^

myvector.resize( std::distance(myvector.begin(),it) ); // 10 20 30 20 10

// using predicate comparison:
std::unique (myvector.begin(), myvector.end(), myfunction);   // (no changes)

// print out content:
std::cout << "myvector contains:";
for (it=myvector.begin(); it!=myvector.end(); ++it)
std::cout << ' ' << *it;
std::cout << '\n';

return 0;
}
Another way to avoid duplicates is using set, int num; string tmp += num; So num could be treated as a character. However, when num > 255, it could be seen as num%256. So,

#include<vector>
#include<stdio.h>
#include<iostream>
#include<set>
#include<map>
#include<algorithm>
#include<string>//不添加string会出现模版的错误
using namespace std;

class Solution {
public:
vector<vector<int> > fourSum(vector<int> &num, int target) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
int nSize = num.size();
vector< vector<int> > result;
if (nSize < 4) return result;

sort(num.begin(), num.end());
vector<int> mid(4);//指定对象的大小为4，mid(4,1)含有4个元素，每个为1

set<string> isExit;
for (int i = 0; i < nSize - 3; ++i)
{
mid[0] = num[i];
for (int j = i + 1; j < nSize - 2; ++j)
{
mid[1] = num[j];
int l = j + 1;
int r = nSize - 1;
int sum = target - num[i] - num[j];
while(l < r)
{
int tmp = num[l] + num[r];
if (sum == tmp)
{
string str;
str += num[i];
str += num[j];
str += num[l];
str += num[r];
set<string>::iterator itr = isExit.find(str);//利用set标记是否被占用
if (itr == isExit.end())
{
isExit.insert(str);
mid[2] = num[l];
mid[3] = num[r];
result.push_back(mid);
}
++l;
--r;
}
else if(sum > tmp)
++l;
else
--r;
}
}
}

return result;
}
};
int main(){
Solution s;
int a[4] = {4,5,6,7};
vector<vector<int> > res;
vector<int> vec(a, a + 4);
res=s.fourSum(vec,26);

return 0;
}
The last way is to use direct comparison.

class Solution {
public:
vector<vector<int> > fourSum(vector<int> &num, int target) {
vector<vector<int> > ret;
if(num.size() < 4) return ret;
sort(num.begin(), num.end());
for(int i = 0; i < num.size(); ++i) {
if (i > 0 && num[i] == num[i - 1])
continue;
for(int j = i + 1; j < num.size(); ++j) {
if (j > i + 1 && num[j] == num[j - 1])
continue;
int left = j + 1;
int right = (int)num.size() - 1;
int sum = 0;
while(left < right){
if (left > j + 1 && num[left] == num[left - 1]) {
++left;
continue;
}
sum=num[i]+num[j]+num[left]+num[right];
if(target == sum){
ret.push_back(vector<int>(4));
ret.back()[0]=num[i];
ret.back()[1]=num[j];
ret.back()[2]=num[left];
ret.back()[3]=num[right];
++left;
--right;
}
else if(sum > target)
--right;
else
++left;
}
}
}
return ret;
}
};


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• <div><p>Allow for unique hostname configuration to differentiate between root certs.</p><p>该提问来源于开源项目：laravel/homestead</p></div>
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• Also, add <strong>unique shortened URL</strong> like my.domain/{alphanumeric chars} for easy linking of the listing using the YOURLS program.</p><p>该提问来源于开源项目：osclass/Osclass</p></...
• <div><h1>Unique key for DataObject (new feature) <p>This change-set adds the capability of <code>DataObject</code> to generate a unique key which can be used as a reliable identifier for the data ...
• <div><h2>Overview <p>Adds key unique_title to the entity definition schema ...<p>This adds unique_title for the purpose <h2>Comments</h2><p>该提问来源于开源项目：civicrm/civicrm-core</p></div>
• <p>I tried to use multiples sequences for a unique button but only the last declaration works. I know it's hard to implement but do you think you can could handle more than one event for a unique ...
• d like to request a slight change to the error that gets thrown for compound unique indexes. It'd be great to throw one error when the single compound index violates uniqueness. The error would ...
• <p>I was searching for possibility to add unique id for checkbox on multiselect column rows but I didn't find such feature. You can either add same id for each checkbox in the multiselect column ...

...