84 lines
1.5 KiB
C++
84 lines
1.5 KiB
C++
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// Source : https://oj.leetcode.com/problems/next-permutation/
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// Author : Hao Chen
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// Date : 2014-08-21
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/*
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1 2 3 4
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1 2 4 3
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1 3 2 4
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1 3 4 2
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1 4 2 3
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1 4 3 2
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2 1 3 4
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...
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <iostream>
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#include <vector>
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#include <algorithm>
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using namespace std;
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void nextPermutation(vector<int> &num) {
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if(num.size()<=1) return;
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for(int i=num.size()-1; i>0; i--) {
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if (num[i-1] < num[i]){
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int j = num.size()-1;
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while( num[i-1] >= num[j]) {
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//pass;
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j--;
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}
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int tmp = num[j];
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num[j] = num[i-1];
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num[i-1] = tmp;
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reverse(num.begin()+i, num.end());
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return;
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}
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if (i == 1 ){
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reverse(num.begin(), num.end());
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return;
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}
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}
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}
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void printVector(vector<int> &num) {
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for(int i=0; i<num.size(); i++) {
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cout << num[i] << " ";
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}
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cout <<endl;
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}
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bool isBeginVector(vector<int> &num) {
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for(int i=0; i<num.size(); i++) {
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if(num[i] != i+1) {
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return false;
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}
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}
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return true;
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}
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int main(int argc, char** argv)
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{
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int n = 4;
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if (argc>1){
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n = atoi(argv[1]);
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}
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vector<int> num;
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for(int i=1; i<=n; i++){
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num.push_back(i);
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}
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while(true){
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printVector(num);
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nextPermutation(num);
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if(isBeginVector(num)){
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break;
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}
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}
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return 0;
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}
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