bzoj4946: [Noi2017]蔬菜 神烦贪心

题目链接

bzoj4946: [Noi2017]蔬菜

题解

挺神的贪心
把第次买的蔬菜拆出来，记下每种蔬菜到期的日期，填第一单位蔬菜比其他的要晚
按价格排序后，贪心的往前面可以填的位置填就可以了。找可以填的位置用并查集维护一下。这样就求出了最大天数的答案。
对于询问的答案，从最后一天往前推，把最便宜的那些丢掉就好了。

代码

#include<cstdio> 
#include<cstring> 
#include<algorithm> 
#define gc getchar  
#define pc putchar
#define int long long
inline int read() { 
    int x = 0,f = 1; 
    char c = getchar(); 
    while(c < '0' || c > '9') c = gc(); 
    while(c <= '9' && c >= '0') x = x * 10 + c - '0',c = gc(); 
    return x * f; 
} 
void print(int x) {
    if(x < 0) { 
        pc('-'); x = -x; 
    } 	 
    if(x >= 10)print(x / 10); 
    pc(x % 10 + '0'); 
} 
const int maxn  = 200007; 
int n,m,k; 
struct node { 
    int a,d,c,x; 
    node(int a = 0,int c = 0,int x = 0,int d = 0) : a(a), c(c),x(x),d(d) {}; 
    bool operator < (const node &k) const {
        return a > k.a; 
    } 
} a[maxn]; 
int tot = 0;
int q[maxn],fa[maxn];  
int find(int x ) { 
    if(fa[x] != x) fa[x] = find(fa[x]); 
    return fa[x]; 
} 
void unionn(int x,int y) {
    int fx = find(x),fy = find(y); 
    if(fx == fy) return ; 
    fa[fy] = fx; 	
} 
int cnt = 0; 
int g[maxn],d[maxn],ga[maxn]; 
int sum = 0; 
void calc(int idx,int c,int a) { 
    sum += 1ll * c * a; 
    g[cnt] += c;ga[cnt] = a; 
    d[idx] += c; 
    if(d[idx] == m) unionn(idx - 1,idx); 
} 
int L[maxn],upd[maxn]; 
int ans[maxn]; 
main() { 
    //freopen("1.in","r",stdin); 
    n = read(),m = read(),k = read(); 
    for(int aa,s,c,x,i = 1;i <= n;++ i) { 
        aa = read(),s = read(),c = read(),x = read(); 
        a[++ tot] = node(aa + s,1,0,x ? (c - 1) / x + 1 : maxn - 7); 
        if(-- c) a[++ tot] = node(aa,c,x,x ? (c - 1) / x + 1 : maxn - 7); 
    } 
    int maxd = 0; 
    for(int i = 1;i <= k;++ i) maxd = std::max(maxd,q[i] = read()); 
    std::sort(a + 1,a + tot + 1); 
    for(int i = 1;i <= maxd;++ i) fa[i] = i; 
    for(int i = 1;i <= tot;++ i) { 
        cnt ++; 
        int idx = find(std::min(a[i].d,maxd)); //a 价值 d GG日期 d 数量 x 每天GG数 
        int res = (idx - 1) * a[i].x ,now = a[i].c - res; 
        while(idx && now) { 
            int mn = std::min(m - d[idx],now); 
            calc(idx,mn,a[i].a); 
            now -= mn; 
            int p = idx; 
            idx = find(idx - 1); 
            p -= idx; 
            if(res) now += p * a[i].x , res -= p * a[i].x; 
        } 
        if(!find(maxd)) break ; 
    } 
    int R = 0; 
    for(int i = 1;i <= maxd;++ i) L[i] = m - d[i] + L[i - 1]; 
    for(int i = maxd;i;-- i) upd[i] = std::max(R - L[i],0ll),R += d[i]; 
    for(int i = maxd;i >= 1;-- i) { 
        ans[i] = sum; 
        int tmp = upd[i - 1] - upd[i]; 
        while(tmp) {
            int mn = std::min(tmp,g[cnt]); 
            sum -= 1ll * ga[cnt] * mn; 
            tmp -= mn; 
            g[cnt] -= mn; 
            if(!g[cnt]) -- cnt; 
        } 
    } 
    for(int i = 1;i <= k;++ i) print(ans[q[i]]),pc('
');// print(10);  
    return 0; 
} // 1110001