Sicily 1027. MJ, Nowhere to Hide

#include<stdio.h>
#include<string.h>

void swap(char a[16], char b[16]);

int main() {
int n = 0, i = 0, j = 0, k = 0, flat = 0, look = 0;
char hold_id[16], hold_ip[16] = {0};
char id[21][16] = {{0}};
char ip[21][16] = {{0}};
char mj[21][16] = {{0}};
while (scanf("%d", &n), n) {
for (i = 0; i < 21; i++) {
id[i][0] = 0;
ip[i][0] = 0;
mj[i][0] = 0;
}
i = 0;
for (k = 0; k < n; k++) {
scanf("%s %s", hold_id, hold_ip);
for (j = 0, flat = 0; j < i; j++) {
if ((strcmp(hold_ip, ip[j])) == 0) {
swap(hold_id, mj[j]);
flat = 1;
break;
}
}
if (!flat) {
swap(id[i], hold_id);
swap(ip[i], hold_ip);
i++;
}
}

for (i = 0; i < n/2 - 1; i++) {
for (j = n/2 - 1; j > i; j--) {
if (strcmp(id[j], id[j-1]) < 0) {
swap(id[j], id[j-1]);
swap(mj[j], mj[j-1]);
}
}
}

for (i = 0; i < n/2; i++) printf("%s is the MaJia of %s\n", mj[i], id[i] );
printf("\n");
}
return 0;
}

void swap(char a[16], char b[16]) {
char hold[16] = {0};
strcpy(hold ,a);
strcpy(a, b);
strcpy(b, hold);
}