Balanced Lineup (POJ-3264) (segment tree)

A very basic line of the tree problem, there is a place to card me for a long time, I am the following code for the interval is left closed to open, so if the desired interval includes the interval endpoint, you need to be in the right interval +1

Segment tree is an efficient data structure, which is characterized by finding the minimum and maximum values in an interval. The data structure feels like a template, but the thought of it should be more worthy of our study, but now there are not a few people can calm down to study the principle of it.

#include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include < queue> #include <vector> #include <map>using namespace std;const int INF = 1000000+10;const int max_n =    50000+100;int n,m,a,b,q,dat[max_n*2-1],dat2[max_n*2-1];void init (int n_) {n = 1;    while (N<n_) n *= 2; for (int i=0;i<2*n-1;i++) dat[i] = INF;}    void Update (int k,int a) {k + = n-1;    Dat[k] = A;        while (k>0) {k= (k-1)/2;    Dat[k] = min (dat[k*2+1],dat[k*2+2]); }}void init2 (int n_) {for (int i=0;i<2*n-1;i++) dat2[i] =-100;}    void Update2 (int k,int a) {k + = n-1;    Dat2[k] = A;        while (k>0) {k = (k-1)/2;    Dat2[k] = max (dat2[k*2+1],dat2[k*2+2]); }}int query (int a,int b,int k,int l,int R) {if (r<=a| |    B&LT;=L) return INF;    if (a<=l&&r<=b) return dat[k];        else {int VL = query (A,b,k*2+1,l, (l+r)/2);        int VR = query (a,b,k*2+2, (l+r)/2,r);    return min (VL,VR); }}int Query2 (int A,int b,int K,int l,int R) {if (r<=a| |    B&LT;=L) return-1;    if (a<=l&&r<=b) return dat2[k];        else {int VL = Query2 (A,b,k*2+1,l, (l+r)/2);        int VR = Query2 (a,b,k*2+2, (l+r)/2,r);    Return Max (VL,VR);    }}int Main () {scanf ("%d%d", &m,&q);    Init (m);    Init2 (m);        for (int i=1;i<=m;i++) {scanf ("%d", &a);        Update (I,A);    Update2 (I,a);    } int maxn = 1000000000;        while (q--) {scanf ("%d%d", &a,&b);        int v = query (a,b+1,0,0,n);        int u = query2 (a,b+1,0,0,n);    printf ("%d\n", u-v); } return 0;}

Balanced Lineup (POJ-3264) (segment tree)