BZOJ2006: [NOI2010]超级钢琴

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cstdlib>
  5 #include <queue>
  6 #include <vector>
  7 #define max(a, b) ((a) > (b) ? (a) : (b))
  8 #define min(a, b) ((a) < (b) ? (a) : (b))
  9 
 10 inline void read(long long &x)
 11 {
 12     x = 0;char ch = getchar(), c = ch;
 13     while(ch < ‘0‘ || ch > ‘9‘)c = ch, ch = getchar();
 14     while(ch <= ‘9‘ && ch >= ‘0‘)x = x * 10 + ch - ‘0‘, ch = getchar();
 15     if(c == ‘-‘)x = -x;
 16 }
 17 
 18 const long long MAXN = 500000 + 10;
 19 const long long MAXK = 500000 + 10;
 20 
 21 long long n,k,l,r,num[MAXN],st[20][MAXN],rank[20][MAXN],M,pow2[30],ans;
 22 
 23 struct Node
 24 {
 25     long long value, l, r, rank, i;
 26     Node(long long _value, long long _l, long long _r, long long _rank, long long _i){value = _value, l = _l, r = _r,rank = _rank;i = _i;}    
 27     Node(){}
 28 };
 29 
 30 struct cmp
 31 {
 32     bool operator()(Node a, Node b)    
 33     {
 34         return a.value < b.value;
 35     }
 36 };
 37 
 38 std::priority_queue<Node, std::vector<Node>, cmp> q;
 39 
 40 void yuchuli()
 41 {
 42     while(pow2[M] <= n)++ M;
 43     --M;
 44     for(register long long i = 1;i <= M;++ i)
 45         for(register long long j = 0;j <= n;++ j)
 46         {
 47             if(j + pow2[i] - 1 > n)continue;
 48             if(st[i - 1][j] < st[i - 1][j + pow2[i - 1]])
 49             {
 50                 st[i][j] = st[i - 1][j];
 51                 rank[i][j] = rank[i - 1][j];
 52             }
 53             else
 54             {
 55                 st[i][j] = st[i - 1][j + pow2[i - 1]];
 56                 rank[i][j] = rank[i - 1][j + pow2[i - 1]];
 57             }
 58         }
 59 }
 60 
 61 long long find(long long l, long long r)
 62 {
 63     if(l > r)
 64     {
 65         long long tmp = l;
 66         l = r;
 67         r = tmp;
 68     }
 69     long long m = 0;
 70     while(pow2[m] <= (r - l + 1))++ m;
 71     -- m;
 72     if(st[m][l] < st[m][r - pow2[m] + 1])
 73         return rank[m][l];
 74     else
 75         return rank[m][r - pow2[m] + 1];
 76 }
 77 
 78 int main()
 79 {
 80     read(n);read(k);read(l);read(r);
 81     pow2[0] = 1;
 82     for(register long long i = 1;i <= 25;++ i)pow2[i] = (pow2[i - 1] << 1);
 83     for(register long long i = 1;i <= n;++ i)
 84     {
 85         read(num[i]);
 86         num[i] += num[i - 1];
 87         st[0][i] = num[i];
 88         rank[0][i] = i;
 89     }
 90     yuchuli();
 91     for(register long long i = l;i <= n;++ i)
 92     {
 93         long long k = find(max(0, i - r), max(i - l, 0));
 94         q.push(Node(num[i] - num[k], max(0, i - r), max(i - l, 0), k, i));
 95     }
 96     long long now = 0;
 97     register Node tmp;
 98     register long long pos;
 99     for(;now < k;++ now)
100     {
101         tmp = q.top(), q.pop();
102         long long l = tmp.l, r = tmp.r;
103         ans += tmp.value; 
104         if(tmp.l <= tmp.rank - 1 && tmp.l >= 0)
105         {
106             pos = find(max(0, tmp.l), max(tmp.rank - 1, 0));
107             q.push(Node(num[tmp.i] - num[pos], tmp.l, tmp.rank - 1, pos, tmp.i));
108         }
109         if(tmp.r >= tmp.rank + 1)
110         {
111             pos = find(max(0, tmp.rank + 1), max(tmp.r, 0));
112             q.push(Node(num[tmp.i] - num[pos], tmp.rank +1, tmp.r, pos, tmp.i));
113         }
114     }
115     printf("%lld", ans);
116     return 0;
117 }