HDU 4296 Buildings [贪心]

　　按S+W排序即可。
 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <algorithm>
 4 #define MAXN 100005
 5 typedef long long LL;
 6 struct ppp{
 7     int s, w;
 8     bool operator < (const ppp& p) const {
 9         return s + w <= p.s + p.w;
10     }
11 }p[MAXN];
12 int n;
13 int main() {
14     while (scanf("%d", &n) != EOF) {
15         for (int i = 0; i < n; i++)
16             scanf("%d%d", &p[i].w, &p[i].s);
17         std::sort(p, p + n);
18         LL ans=0, totw = 0;
19         for (int i = 0; i < n; i++)
20             ans = std::max(ans, totw - p[i].s),
21             totw += p[i].w;
22         printf("%I64d\n", ans);
23     }
24     return 0;
25 }