UVALive - 4725 Airport

UVALive - 4725

每一次只能出去一架飞机,对答案进行二分

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#define INF 0x3f3f3f3f
#define eps 1e-6
#define PI 3.1415926
#define mod 1000000007
#define base 2333
using namespace std;
typedef long long LL;
const int inf = 1e9;
const int maxn = 5e3 + 10;
const int maxx = 5e6 + 10;
int t, n, a[maxn], b[maxn];

int check(int k) {
    int sa = 0, sb = 0, aa = 0, bb = 0, cnt = 0;
    for(int i = 0; i < n; i++) {
        sa += a[i], sb += b[i];
        if(a[i] > k || b[i] > k)
            return 0;
        while(sa > k) {
            if(aa == 0 || cnt == 0)
                return 0;
            sa--, aa--, cnt--;
        }
        while(sb > k) {
            if(bb == 0 || cnt == 0)
                return 0;
            sb--, bb--, cnt--;
        }
        if(aa < sa)  aa++;
        if(bb < sb)  bb++;
        if(sa+sb > cnt)  cnt++;
    }
    return 1;
}

void solve() {
    scanf("%d", &t);
    while(t--) {
        scanf("%d", &n);
        for(int i = 0; i < n; i++)
            scanf("%d%d", &a[i], &b[i]);
        int l = 1, r = maxn*20, mid;
        while(l < r) {
            mid = (l+r)>>1;
            if(check(mid)) r = mid;
            else  l = mid+1;
        }
        printf("%d\n", l-1);
    }
}

int main() {
    //srand(time(NULL));
    //freopen("perechi3.in","r",stdin);
    //freopen("perechi3.out","w",stdout);
    solve();
}


你可能感兴趣的:(贪心,二分)