LeetCode_38combinationSum [Combination Sum]

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#pragma warning(disable:4996)

#include <cstdio>
#include <tchar.h>
#include <Windows.h>
#include <vector>
using namespace std;

/*
	submit time : 4
		1.Runtime Error
			Last executed input:	[1], 2			// Find it
		2. Wrong Answer
			Input:	[2,3,5], 7
			Output:	[[2,2,3]]
			Expected:	[[2,2,3],[2,5]]
		3. Wrong Answer
			Input:	[1,2], 2
			Output:	[[1,1],[2],[2]]
			Expected:	[[1,1],[2]]
	request :
		Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.

		The same repeated number may be chosen from C unlimited number of times.

		Note:
		All numbers (including target) will be positive integers.
		Elements in a combination (a1, a2, … , ak) must be in non-descending order. (ie, a1 ≤ a2 ≤ … ≤ ak).
		The solution set must not contain duplicate combinations.
		For example, given candidate set 2,3,6,7 and target 7,
		A solution set is:
		[7]
		[2, 2, 3]
*/

//=================QuickSort===================
void Swap(int* data, int i, int j) {
	int temp = data[i];
	data[i] = data[j];
	data[j] = temp;
}

int findpivot(int* data, int i, int j) {
	return (i + j) >> 1;
}

int partition(int* data, int l, int r, int pivot) {
	while (l < r) {
		while (data[++l] < pivot);
		while (l<r && data[--r] > pivot);
		Swap(data, l, r);
	}

	return l;
}

void qsort(int* data, int i, int j) {
	if (j <= i) return;

	int pivotIndex = findpivot(data, i, j);
	Swap(data, pivotIndex, j);
	int k = partition(data, i - 1, j, data[j]);
	Swap(data, k, j);
	qsort(data, i, k - 1);
	qsort(data, k + 1, j);
}
//===================END=======================

void helpCombinationSum(vector<vector<int> >& result, vector<int>& solution, int* pStart, int* pLast, int* vernier, int target) {
	if (target == 0) {
		result.push_back(solution);
		return;
	}
	if ((vernier <= pLast && target < *vernier) || (vernier > pLast))
		return;

	int currValue = *vernier;
	int maxCount = target / currValue;
	int rem = target % currValue;

	int i = maxCount;
	while (i) {
		solution.push_back(currValue);
		--i;
	}
	while (maxCount >= 0) {
		helpCombinationSum(result, solution, pStart, pLast, vernier + 1, target - currValue*maxCount);
		if (maxCount)
			solution.pop_back();
		--maxCount;
	}
}

vector<vector<int> > combinationSum(vector<int> &candidates, int target) {
	vector<vector<int> > result;
	if (candidates.size() == 0) return result;

	vector<int> solution;
	int* vernier = &candidates[0];
	int length = candidates.size();
	int* firstCandidate = vernier;
	int* lastCandidate = vernier + length - 1;

	// sort candidates
	qsort(vernier, 0, length - 1);

	// submit failed here
	/*while (vernier <= lastCandidate) {
		helpCombinationSum(result, solution, firstCandidate, lastCandidate, vernier, target);
		++vernier;
	}*/
	helpCombinationSum(result, solution, firstCandidate, lastCandidate, vernier, target);

	return result;
}

//======================Test========================
void printVector(vector<int>& num) {
	vector<int>::iterator iter = num.begin();
	for (; iter != num.end(); ++iter)
		printf("%d ", *iter);
	printf("\n");
}

void Test() {
	//int data[] = { 9, 31, 25, 5, 8, 6, 16 };
	int data[] = { 2,3,5 };
	int target = 7;
	vector<int> candidates(data, data + sizeof(data) / sizeof(int));
	vector<vector<int> > result = combinationSum(candidates, target);
	vector<vector<int> >::iterator iter = result.begin();
	for (; iter != result.end(); ++iter)
		printVector(*iter);
}

int _tmain(int argc, _TCHAR* argv[]) {
	Test();

	system("pause");
	return 0; 
}

LeetCode_38combinationSum [Combination Sum],布布扣,bubuko.com

LeetCode_38combinationSum [Combination Sum]

标签：des   os   io   art   for   re   

原文地址：http://my.oschina.net/ITHaozi/blog/292534