64 lines
2.4 KiB
C++
64 lines
2.4 KiB
C++
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// Source : https://leetcode.com/problems/find-the-winner-of-the-circular-game/
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// Author : Hao Chen
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// Date : 2021-04-11
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/*****************************************************************************************************
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*
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* There are n friends that are playing a game. The friends are sitting in a circle and are numbered
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* from 1 to n in clockwise order. More formally, moving clockwise from the i^th friend brings you to
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* the (i+1)^th friend for 1 <= i < n, and moving clockwise from the n^th friend brings you to the
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* 1^st friend.
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*
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* The rules of the game are as follows:
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*
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* Start at the 1^st friend.
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* Count the next k friends in the clockwise direction including the friend you started at.
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* The counting wraps around the circle and may count some friends more than once.
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* The last friend you counted leaves the circle and loses the game.
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* If there is still more than one friend in the circle, go back to step 2 starting from the
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* friend immediately clockwise of the friend who just lost and repeat.
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* Else, the last friend in the circle wins the game.
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*
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* Given the number of friends, n, and an integer k, return the winner of the game.
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*
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* Example 1:
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*
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* Input: n = 5, k = 2
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* Output: 3
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* Explanation: Here are the steps of the game:
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* 1) Start at friend 1.
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* 2) Count 2 friends clockwise, which are friends 1 and 2.
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* 3) Friend 2 leaves the circle. Next start is friend 3.
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* 4) Count 2 friends clockwise, which are friends 3 and 4.
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* 5) Friend 4 leaves the circle. Next start is friend 5.
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* 6) Count 2 friends clockwise, which are friends 5 and 1.
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* 7) Friend 1 leaves the circle. Next start is friend 3.
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* 8) Count 2 friends clockwise, which are friends 3 and 5.
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* 9) Friend 5 leaves the circle. Only friend 3 is left, so they are the winner.
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*
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* Example 2:
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*
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* Input: n = 6, k = 5
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* Output: 1
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* Explanation: The friends leave in this order: 5, 4, 6, 2, 3. The winner is friend 1.
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*
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* Constraints:
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*
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* 1 <= k <= n <= 500
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******************************************************************************************************/
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class Solution {
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public:
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int findTheWinner(int n, int k) {
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vector<int> persons(n);
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for(int i=0; i<n; i++) persons[i] = i + 1;
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for(int start=0; n>1; n--){
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start = (start + k -1) % n;
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persons.erase(persons.begin() + start);
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start = start %(n-1);
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}
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return persons[0];
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}
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};
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