## Solución al problema número 12532 de UVA - 12532.

Cualquier duda no dudes en contactar.

``````#include <bits/stdc++.h>
using namespace std;

void buildTree(int *tree,int *a,int index,int s,int e)
{
//base case
if(s>e)
return;
//reached leaf node
if(s==e)
{
tree[index]=a[s];
return ;
}
//now build the segment tree in bottom up manner
int m = (s+e)/2;
buildTree(tree,a,2*index,s,m);
buildTree(tree,a,2*index+1,m+1,e);
tree[index]= tree[2*index]*tree[2*index+1];
return;
}

//function to query the segment tree for RSQ
int query(int *tree,int index,int s,int e,int qs,int qe)
{
//base case: if query range is outside the node range
if(qs>e || s>qe)
return 1;
//complete overlap
if(s>=qs && e<=qe)
return tree[index];
//now partial overlap case is executed
int m = (s+e)/2;
int left_ans = query(tree,2*index,s,m,qs,qe);
int right_ans = query(tree,2*index+1,m+1,e,qs,qe);
return left_ans*right_ans;
}

//function to update a value at position to "pos"
void updateNode(int *tree,int index,int s,int e,int pos,int val)
{
if(pos<s || pos>e)
return ;
if(s==e)
{
tree[index] = val;
return ;
}
int m = (s+e)/2;
updateNode(tree,2*index,s,m,pos,val);
updateNode(tree,2*index+1,m+1,e,pos,val);
tree[index] = tree[2*index]*tree[2*index+1];
return;
}

int main()
{
int n,c;
while(scanf("%d %d",&n,&c)==2)
{
int a[n];
for(int i=0; i<n; i++) { scanf("%d",&a[i]); if(a[i]<0) a[i]=-1; if(a[i]>0) a[i]=1;}
int *tree = new int[4*n+1];                                    //array to store the segment tree
int index = 1;													//index of 1st node
int s =0,e=n-1;
buildTree(tree,a,index,s,e);									//now tree has been built
for(int i=0; i<c;i++)
{
char ca; cin.ignore();
int j,k; scanf("%c %d %d",&ca,&j,&k);
if(ca=='C') {if(k<0) k=-1; if(k>0) k=1;  updateNode(tree,index,s,e,j-1,k); }
else
{
int sol = query(tree,index,s,e,j-1,k-1);
if(sol==0)  printf("0");
else if(sol<0) printf("-");
else printf("+");
}
}
printf("\n");
}
return 0;
}
``````