A Villages: Landlines

题意 ：

求所有区间之间的距离和（注意有包含关系的不用累加）

#include <iostream>#include <algorithm>using namespace std;const int N = 2e5 + 10;typedef long long ll;ll n;struct node {ll l, r;}a[N];bool cmp(node a, node b) {if (a.l != b.l) return a.l < b.l;return a.r < b.r;}int main() {cin >> n;for (int i = 1; i <= n; ++ i) {int p, r;cin >> p >> r;a[i].l = p - r;a[i].r = p + r;}sort(a + 1, a + n + 1, cmp);ll ans = 0, last = a[1].r;for (int i = 2; i <= n; ++ i) {if (a[i].l > last) {ans += (a[i].l - last);}last = max(last, a[i].r);}cout << ans;}