我用网络流过了，呵呵，SAP很强大。
#include <stdio.h>
#include <string.h>
#define oo 0x7fffffff
#define MAXM 690000
#define MAXN 5003
typedef struct{int u; int v; int cap; int next;}edge_t;
edge_t e[MAXM * 2];
int first[MAXN];
int dist[MAXN];
int now[MAXN];
int pre[MAXN];
int cnt[MAXN];
int cur[MAXN];
int tot, n;
void add(int u, int v, int cap)
{
e[++tot].u = u; e[tot].v = v; e[tot].cap = cap; e[tot].next = first[u]; first[u] = tot;
e[++tot].u = v; e[tot].v = u; e[tot].cap = 0; e[tot].next = first[v]; first[v] = tot;
}
void init()
{
int covers, spf, st, ed;
int c, l, i, j;
scanf("%d %d", &c, &l);
for(i = 1;i <= c; i++) scanf("%d %d", &cnt[i], &cur[i]);
memset(first, -1, sizeof(first)); tot = -1;
st = 1;
ed = c + l + 2;
for(i = 1;i <= l; i++)
{
scanf("%d %d", &spf, &covers);
add(st, i + 1, covers);
for(j = 1;j <= c; j++) if(cnt[j] <= spf && spf <= cur[j]) add(i + 1, l + j + 1, oo);
}
for(i = 1;i <= c; i++) add(l + i + 1, ed, 1);
n = ed;
}
int sap()
{
int tot_flow;
int now_flow, found, min;
int st, ed, i, j, t;
memset(dist, 0, sizeof(dist));
memset(now, -1, sizeof(now));
memset(cnt, 0, sizeof(cnt));
st = 1; ed = n; i = st;
tot_flow = 0; now_flow = oo;
cnt[0] = n;
while(dist[st] < n)
{
cur[i] = now_flow; found = 0;
if(now[i] == -1) t = first[i];
else t = now[i];
while(t != -1)
{
j = e[t].v;
if(e[t].cap > 0 && dist[j] + 1 == dist[i])
{
found = 1; now[i] = t;
if(e[t].cap < now_flow) now_flow = e[t].cap;
pre[j] = t; i = j;
if(i == ed)
{
tot_flow += now_flow;
while(i != st)
{
e[pre[i]].cap -= now_flow;
e[pre[i]^1].cap += now_flow;
i = e[pre[i]].u;
}
now_flow = oo;
}
break;
}
t = e[t].next;
}
if(found) continue;
if(--cnt[dist[i]] == 0) break;
min = n - 1;
t = first[i];
while(t != -1)
{
if(e[t].cap > 0 && dist[e[t].v] < min)
{
min = dist[e[t].v];
now[i] = t;
}
t = e[t].next;
}
dist[i] = min + 1;
cnt[dist[i]]++;
if(i != st)
{
i = e[pre[i]].u;
now_flow = cur[i];
}
}
return tot_flow;
}
int main()
{
int res;
init();
res = sap();
printf("%d\n", res);
return 0;
}
