3175-FindTheFirstPlayerToWinKGamesInARow.go

package main

// 3175. Find The First Player to win K Games in a Row
// A competition consists of n players numbered from 0 to n - 1.

// You are given an integer array skills of size n and a positive integer k, where skills[i] is the skill level of player i. 
// All integers in skills are unique.

// All players are standing in a queue in order from player 0 to player n - 1.

// The competition process is as follows:
//     1. The first two players in the queue play a game, and the player with the higher skill level wins.
//     2. After the game, the winner stays at the beginning of the queue, and the loser goes to the end of it.

// The winner of the competition is the first player who wins k games in a row.

// Return the initial index of the winning player.

// Example 1:
// Input: skills = [4,2,6,3,9], k = 2
// Output: 2
// Explanation:
// Initially, the queue of players is [0,1,2,3,4]. The following process happens:
// Players 0 and 1 play a game, since the skill of player 0 is higher than that of player 1, player 0 wins. The resulting queue is [0,2,3,4,1].
// Players 0 and 2 play a game, since the skill of player 2 is higher than that of player 0, player 2 wins. The resulting queue is [2,3,4,1,0].
// Players 2 and 3 play a game, since the skill of player 2 is higher than that of player 3, player 2 wins. The resulting queue is [2,4,1,0,3].
// Player 2 won k = 2 games in a row, so the winner is player 2.

// Example 2:
// Input: skills = [2,5,4], k = 3
// Output: 1
// Explanation:
// Initially, the queue of players is [0,1,2]. The following process happens:
// Players 0 and 1 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is [1,2,0].
// Players 1 and 2 play a game, since the skill of player 1 is higher than that of player 2, player 1 wins. The resulting queue is [1,0,2].
// Players 1 and 0 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is [1,2,0].
// Player 1 won k = 3 games in a row, so the winner is player 1.

// Constraints:
//     n == skills.length
//     2 <= n <= 10^5
//     1 <= k <= 10^9
//     1 <= skills[i] <= 10^6
//     All integers in skills are unique.

import "fmt"

// 双指针
func findWinningPlayer(skills []int, k int) int {
    low, high, count := 0, 1, 0
    for ; high < len(skills) && count < k; high++ {
        if skills[low] > skills[high] {
            count++
        } else {
            count, low = 1, high
        }
    }
    return low
}

func main() {
    // Example 1:
    // Input: skills = [4,2,6,3,9], k = 2
    // Output: 2
    // Explanation:
    // Initially, the queue of players is [0,1,2,3,4]. The following process happens:
    // Players 0 and 1 play a game, since the skill of player 0 is higher than that of player 1, player 0 wins. The resulting queue is [0,2,3,4,1].
    // Players 0 and 2 play a game, since the skill of player 2 is higher than that of player 0, player 2 wins. The resulting queue is [2,3,4,1,0].
    // Players 2 and 3 play a game, since the skill of player 2 is higher than that of player 3, player 2 wins. The resulting queue is [2,4,1,0,3].
    // Player 2 won k = 2 games in a row, so the winner is player 2.
    fmt.Println(findWinningPlayer([]int{4,2,6,3,9}, 2)) // 2
    // Example 2:
    // Input: skills = [2,5,4], k = 3
    // Output: 1
    // Explanation:
    // Initially, the queue of players is [0,1,2]. The following process happens:
    // Players 0 and 1 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is [1,2,0].
    // Players 1 and 2 play a game, since the skill of player 1 is higher than that of player 2, player 1 wins. The resulting queue is [1,0,2].
    // Players 1 and 0 play a game, since the skill of player 1 is higher than that of player 0, player 1 wins. The resulting queue is [1,2,0].
    // Player 1 won k = 3 games in a row, so the winner is player 1.
    fmt.Println(findWinningPlayer([]int{2,5,4}, 3)) // 1
}