t.c

#include <stdio.h>
int x[100001];
int y[100001];
int flag[100001] = {0};

int min(int a, int b) {
    return a > b ? b : a;
};
int abs(int x) {
    return x > 0 ? x : -x;
};
int main() {
    int n;
    int i;
    int c = 0;
    int next = 0;
    int min_steps, this_steps;
    long long sum = 0;
    scanf("%d", &n);
    for (i = 0; i < n; i++) {
        scanf("%d%d", &x[i], &y[i]);
    }
    while (c < n) {
        c++;
        flag[next] = 1;
        min_steps = 1000000001;
        for (i = 0; i < n; i++) {
            if (flag[i] == 0) {
                this_steps = min(abs(x[next] - x[i]), abs(y[next] - y[i]));
                if (this_steps < min_steps) {
                    min_steps = this_steps;
                    next = i;
                }
            }
        }
        if (min_steps == 1000000001) {
            min_steps = 0;
        }
        sum += min_steps;
    }
    printf("%lld\n", sum);
    return 0;
}