HDU more than 1754 students steal grades ask highest score-line tree-(single point substitution, interval maximum)

Test instructions: N students have initial scores, now have M operations, (Q,A,B): Ask the interval number for [A, b] students of the best results; (U,A,B): The student who modified the number A is a B, want you to perform this m operation.

Analysis:

Single point update, interval query. is a single point of substitution, interval query. The two typical uses of a line segment.

Code:

#include <iostream> #include <cstdio> #include <algorithm> using namespace std;const int maxn=200000; int n,m;int mx[maxn*4+10];void pushup (int rt) {Mx[rt]=max (mx[rt<<1],mx[rt<<1|1]);} void creat (int l,int r,int RT) {if (l==r) {//L==r leaf node, which represents a specific student//mx[rt]=0;//If you first build and then use the UPD to update the initial value, then you should first assign the initial values here, or the program Pushup () The operation will be problematic. Assign any value to the line, because the scanf ("%d", &mx[rt]) is updated when the initial value is entered; In this case, the direct initialization is also the return;} int mid= (L+R) >>1; Creat (l,mid,rt<<1); creat (mid+1,r,rt<<1|1);p ushup (RT);} void upd (int a,int x,int l,int r,int RT) {if (l==r) {//leaf node, if student A is found, then update his score Mx[rt]=x;return;} int mid= (L+R) >>1;  if (a<=mid) upd (a,x,l,mid,rt<<1);        If a is in the left interval, go to the left section to find him, and then update his score else UPD (a,x,mid+1,r,rt<<1|1);     If in the right interval, go to the right interval to find him pushup (RT);   Find student a update his score to update the maximum range of the interval}int query (int a,int b,int l,int r,int RT) {if (a<=l&&b>=r) return MX[RT];        If the query interval contains the current interval, then return the interval maximum value int mid= (L+R) >>1; Otherwise, the maximum value is found in the left sub-interval of the current interval, and the right sub-range is searched for the maximum value and then returns the maximum value int ret=0;if (A&LT;=MID) Ret=max (ret, query (a,b,l,mid,rt<<1)), if (B>mid) Ret=max (Ret,query (a,b,mid+1,r,rt<<1|1)); return ret; } int main () {while (scanf ("%d%d", &n,&m)!=eof) {creat (1,n,1);//for (int i=1;i<=n;i++) {////build again update the initial value with update operation can also, However, we must first assign the initial value//int a;//scanf ("%d", &a),//UPD (i,a,1,n,1),//}while (m--) {char a[10]; int b,c;scanf ("%s%d%d", &a , &b,&c); You cannot use%c because%c is an if (a[0]== ' Q ') printf ("%d\n", Query (b,c,1,n,1)) that does not filter spaces and newline characters, and Else upd (b,c,1,n,1);}}

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HDU more than 1754 students steal grades ask highest score-line tree-(single point substitution, interval maximum)