Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 1437 Accepted Submission(s): 690
这题就是查询一个区间内小于等于一个数的数的个数。
用树状数组离线搞过。
修改下划分树模板也可以搞定
#include <stdio.h> #include <string.h> #include <algorithm> #include <string.h> using namespace std; const int MAXN = 100010; int tree[20][MAXN]; int sorted[MAXN]; int toleft[20][MAXN]; void build(int l,int r,int dep) { if(l == r)return; int mid = (l+r)>>1; int same = mid-l+1; for(int i = l;i <= r;i++) if(tree[dep][i] < sorted[mid]) same--; int lpos = l; int rpos = mid+1; for(int i = l;i <= r;i++) { if(tree[dep][i] < sorted[mid]) tree[dep+1][lpos++] = tree[dep][i]; else if(tree[dep][i] == sorted[mid] && same > 0) { tree[dep+1][lpos++] = tree[dep][i]; same--; } else tree[dep+1][rpos++] = tree[dep][i]; toleft[dep][i] = toleft[dep][l-1] + lpos - l; } build(l,mid,dep+1); build(mid+1,r,dep+1); } //查询区间[l,r]上比k小于等于的数的个数 int query(int L,int R,int l,int r,int dep,int k) { //printf("%d %d %d %d %d %d\n",L,R,l,r,dep,k); if(l == r) { if(tree[dep][l] <= k)return 1; else return 0; } int mid = (L+R)>>1; int cnt = toleft[dep][r] - toleft[dep][l-1]; if(sorted[mid] <= k) { int newr = r + toleft[dep][R] - toleft[dep][r]; int newl = newr - (r-l+1-cnt) + 1; return cnt + query(mid+1,R,newl,newr,dep+1,k); } else { int newl = L + toleft[dep][l-1] - toleft[dep][L-1]; int newr = newl + cnt -1; if(newr >= newl)return query(L,mid,newl,newr,dep+1,k); else return 0; } } int main() { int T; int iCase = 0; scanf("%d",&T); int n; while(T--) { iCase ++; int m; scanf("%d%d",&n,&m); memset(tree,0,sizeof(tree)); memset(toleft,0,sizeof(toleft)); for(int i = 1;i <= n;i++) { scanf("%d",&tree[0][i]); sorted[i] = tree[0][i]; } sort(sorted+1,sorted+n+1); build(1,n,0); int L,R,H; printf("Case %d:\n",iCase); while(m--) { scanf("%d%d%d",&L,&R,&H); L++;R++; printf("%d\n",query(1,n,L,R,0,H)); } } return 0; }