【PAT甲级】1031. Hello World for U (20)

#include <stdio.h>#include <string.h>int main(int argc, char *argv[]) {    int n, n1, n2, n3;    char a[81];    scanf("%s", a);    n = strlen(a);    if (n % 2 == 0) n2 = 4;    else n2 = 3;    n1 = n3 = (n + 2 - n2) / 2;    while (n1 > n2) {        n1--;        n3--;        n2 += 2;    }    int i, j, k;    for (i = 0; i < n1; i++) {        if (i < n1 - 1) {            for (j = 0; j < n2; j++) {                if (j == 0) {                    printf("%c", a[i]);                } else if (j == n2 - 1) {                    printf("%c", a[n - 1 - i]);                } else {                    printf(" ");                }            }        } else {            for (j = n1 - 1; j < n1 + n2 - 1; j++)                printf("%c", a[j]);        }        printf("\n");    }    return 0;}