Luogu2869 [USACO07DEC]美食的食草动物Gourmet Grazers (贪心,二分,数据结构优化)
贪心
考场上因无优化与卡常T掉的\(n \log(n)\)
//#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Abs(a) ((a) < 0 ? -(a) : (a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long
#define ON_DEBUG
#ifdef ON_DEBUG
#define D_e_Line printf("\n\n----------\n\n")
#define D_e(x) cout << #x << " = " << x << endl
#define Pause() system("pause")
#define FileOpen() freopen("in.txt","r",stdin);
#else
#define D_e_Line ;
#define D_e(x) ;
#define Pause() ;
#define FileOpen() ;
#endif
struct ios{
template<typename ATP>ios& operator >> (ATP &x){
x = 0; int f = 1; char c;
for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-') f = -1;
while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
x*= f;
return *this;
}
}io;
using namespace std;
const int N = 100007;
struct Day{
long long cost, taste;
bool operator < (const Day &com) const{
if(taste != com.taste) return taste > com.taste;
return cost > com.cost;
}
}day[N];
struct Food{
long long cost, taste;
bool operator < (const Food &com) const{
if(cost != com.cost) return cost < com.cost;
return taste < com.taste;
}
}food[N];
int n, m;
inline int FindFood(int price){
int l = 1, r = m;
while(l <= r){
int mid = (l + r) >> 1;
if(food[mid].cost >= price)
r = mid - 1;
else
l = mid + 1;
}
return l;
}
int vis[N];
int main(){
freopen("snack.in", "r", stdin);
freopen("snack.out", "w", stdout);
io >> n >> m;
R(i,1,n){
io >> day[i].cost >> day[i].taste;
}
R(i,1,m){
io >> food[i].cost >> food[i].taste;
}
if(m < n){
printf("-1");
return 0;
}
sort(day + 1, day + n + 1);
sort(food + 1, food + m + 1);
long long ans = 0;
R(i,1,n){
int pos = FindFood(day[i].cost);
while(vis[pos] == true) ++pos;
if(pos > m){
printf("-1"); return 0;
}
int flag = 0;
R(j,pos,m){
if(vis[j]) continue;
if(food[j].taste >= day[i].taste){
vis[j] = true;
ans += food[j].cost;
flag = 1;
break;
}
}
if(!flag){
printf("-1"); return 0;
}
}
printf("%lld", ans);
return 0;
}
/*
one money raise
one taste down
4 7
1 1
2 3
1 4
4 2
3 2
2 1
4 3
5 2
5 4
2 6
4 4
*/
正解用数据结构,或STL水
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Abs(a) ((a) < 0 ? -(a) : (a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long
#define ON_DEBUG
#ifdef ON_DEBUG
#define D_e_Line printf("\n\n----------\n\n")
#define D_e(x) cout << #x << " = " << x << endl
#define Pause() system("pause")
#define FileOpen() freopen("in.txt","r",stdin);
#else
#define D_e_Line ;
#define D_e(x) ;
#define Pause() ;
#define FileOpen() ;
#endif
struct ios{
template<typename ATP>ios& operator >> (ATP &x){
x = 0; int f = 1; char c;
for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-') f = -1;
while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
x*= f;
return *this;
}
}io;
using namespace std;
#include <set>
const int N = 100007;
multiset<int> st;
pair<int,int> day[N], food[N];
int main(){
//FileOpen();
int n,m;
io >> n >> m;
R(i,1,n){
io >> day[i].second >> day[i].first;
}
R(i,1,m){
io >> food[i].second >> food[i].first;
}
sort(day + 1, day + n + 1);
sort(food + 1, food + m + 1);
int j = m;
long long ans = 0;
nR(i,n,1){
while(j && food[j].first >= day[i].first){
st.insert(food[j].second);
--j;
}
multiset<int>::iterator it = st.lower_bound(day[i].second);
if(it == st.end()){
printf("-1"); return 0;
}
ans += *it;
st.erase(it);
}
printf("%lld", ans);
return 0;
}