CodeForces - 1538A Stone Game博弈

Posted 2022-05-17 海岛Blog

A. Stone Game
time limit per test2 seconds
memory limit per test256 megabytes

Polycarp is playing a new computer game. This game has n stones in a row. The stone on the position i has integer power ai. The powers of all stones are distinct.

Each turn Polycarp can destroy either stone on the first position or stone on the last position (in other words, either the leftmost or the rightmost stone). When Polycarp destroys the stone it does not exist any more.

Now, Polycarp wants two achievements. He gets them if he destroys the stone with the least power and the stone with the greatest power. Help Polycarp find out what is the minimum number of moves he should make in order to achieve his goal.

For example, if n=5 and a=[1,5,4,3,2], then Polycarp could make the following moves:

Destroy the leftmost stone. After this move a=[5,4,3,2];
Destroy the rightmost stone. After this move a=[5,4,3];
Destroy the leftmost stone. After this move a=[4,3]. Polycarp destroyed the stones with the greatest and least power, so he can end the game.
Please note that in the example above, you can complete the game in two steps. For example:

Destroy the leftmost stone. After this move a=[5,4,3,2];
Destroy the leftmost stone. After this move a=[4,3,2]. Polycarp destroyed the stones with the greatest and least power, so he can end the game.

Input
The first line contains an integer t (1≤t≤100). Then t test cases follow.

The first line of each test case contains one integer n (2≤n≤100) — the number of stones.

The second line contains n distinct integers a1,a2,…,an (1≤ai≤n) — the power of the stones.

Output
For each test case, output the minimum number of moves required to destroy the stones with the greatest and the lowest power.

Example
input
5
5
1 5 4 3 2
8
2 1 3 4 5 6 8 7
8
4 2 3 1 8 6 7 5
4
3 4 2 1
4
2 3 1 4
output
2
4
5
3
2

问题链接：CodeForces - 1538A Stone Game
问题简述：（略）
问题分析：这里给出2个解题程序。

AC的C++语言程序如下：

/* CodeForces - 1538A Stone Game */

#include <iostream>
#include <cstdio>

using namespace std;

int main()

    int t, n, a;
    scanf("%d", &t);
    while (t--) 
        scanf("%d", &n);

        int l = 0; int r = n - 1;
        for (int i = 1; i <= n; i++) 
            scanf("%d", &a);
            if (a == 1) l = i;
            else if (a == n) r = i;
        

        if (l > r) swap(l, r);
        int ans = __min(r, l + (n - r +1));
        ans = __min(ans, n - l + 1);

        printf("%d\\n", ans);
    

    return 0;

AC的C++语言程序如下：

/* CodeForces - 1538A Stone Game */

#include <iostream>
#include <algorithm>
#include <cstdio>

using namespace std;

const int N = 100;
int a[N];

int main()

    int t, n;
    scanf("%d", &t);
    while (t--) 
        scanf("%d", &n);
        for (int i = 0; i < n; i++)
            scanf("%d", &a[i]);

        int maxp = max_element(a, a + n) - a;   // 最大值位置
        int minp = min_element(a, a + n) - a;   // 最小值位置
        int ans = min(max(maxp, minp) + 1, max(n - maxp, n - minp), 
                       minp + 1 + n - maxp, maxp + 1 + n - minp);

        printf("%d\\n", ans);
    

    return 0;