算法竞赛入门经典_3.1_数组_逆序输出_开灯问题

#include 
//逆序输出 2017-8-16
#define maxn 105
int a[maxn];
int main(int argc, char* argv[])
{
    //int a[maxn];
    int x, n = 0;
    while (scanf("%d", &x) == 1)
        a[n++] = x;
    for (int i = n - 1; i >= 1; i--)
        printf("%d ", a[i]);
    printf("%d\n", a[0]);//输出的行首和行尾一般均无空格,所以用两条语句实现输出
    return 0;
}

//开灯问题 2017-8-16

#include 
#include <string.h>
#define maxn 1010
int a[maxn];
int main(int argc, char* argv[])
{
    int n, k, first = 1;
    memset(a, 0, sizeof(a));
    scanf("%d%d", &n, &k);
    for (int i = 1; i <= k; i++)
        for (int j = 1; j <= n; j++)
            if (j % i == 0) a[j] = !a[j];
    for(int i = 1; i <= n; i++)
        if(a[i])
        {
            if (first) first = 0;
            else
                printf(" ");
            printf("%d", i);
        }
    printf("\n");
    return 0;
}

//蛇形填数问题 2017-8-16
#include 
#include <string.h>
#define maxn 20
int a[maxn][maxn];
int main()
{
    int n, x, y, tot = 0;
    scanf("%d", &n);
    memset(a, 0, sizeof(a));
    x = 0;
    y = n - 1;
    a[x][y] = 1;
    tot = 1;
    //tot = a[x = 0][y = n - 1] = 1;//这条语句很简洁,也可以使用这句替代上面的四条语句
    while (tot n)
    {
        while (x + 1 1][y])
            a[++x][y] = ++tot;
        while (y - 1 >= 0 && !a[x][y - 1])
            a[x][--y] = ++tot;
        while (x - 1 >= 0 && !a[x - 1][y])
            a[--x][y] = ++tot;
        while (y + 1 1])
            a[x][++y] = ++tot;
    }
    for (x = 0; x )
    {
        for (y = 0; y )
            printf("%3d", a[x][y]);
        printf("\n");
    }
    return 0;
}