Algorithm
Problem link- https://www.spoj.com/problems/UPDATEIT/
UPDATEIT - Update the array !
You have an array containing n elements initially all 0. You need to do a number of update operations on it. In each update you specify l, r and val which are the starting index, ending index and value to be added. After each update, you add the 'val' to all elements from index l to r. After 'u' updates are over, there will be q queries each containing an index for which you have to print the element at that index.
Input
First line consists of t, the number of test cases. (1 <= t <= 10)
Each test case consists of "n u",number of elements in the array and the number of update operations, in the first line (1 <= n <= 10000 and 1 <= u <= 100000)
Then follow u lines each of the format "l r val" (0 <= l,r < n, 0 <= val <=10000)
Next line contains q, the number of queries. (1 <= q <= 10000)
Next q lines contain an index (0 <= index < n)
Output
For each test case, output the answers to the corresponding queries in separate lines.
Example
Input: 1
5 3
0 1 7
2 4 6
1 3 2
3
0
3
4
Output:
7
8
6
Code Examples
#1 Code Example with C++ Programming
Code -
C++ Programming
#include <bits/stdc++.h>
#include <limits.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;
#define MOD (ll)1000000007
#define pb push_back
#define EPS 1e-9
#define FOR(i,n) for(int i = 0;i < n; i++)
#define FORE(i,a,b) for(int i = a;i <= b; i++)
#define pi(a) printf("%d\n", a)
#define all(c) c.begin(), c.end()
#define tr(container, it) for(typeof(container.begin()) it = container.begin(); it != container.end(); it++)
#define gc getchar_unlocked
#define sdi(a, b) si(a);si(b)
#define io ios_base::sync_with_stdio(false);cin.tie(NULL);
#define endl '\n'
#define F first
#define S second
#define FILL(arr, val) memset(arr, val, sizeof(arr))
#define read(arr, n) for(int i = 0;i < n; i++)cin>>arr[i];
#define sp ' '
template <typename T> T gcd(T a, T b){return (b==0)?a:gcd(b,a%b);}
template <typename T> T lcm(T a, T b){return a*(b/gcd(a,b));}
template <typename T> T mod_exp(T b, T p, T m){T x = 1;while(p){if(p&1)x=(x*b)%m;b=(b*b)%m;p=p>>1;}return x;}
template <typename T> T invFermat(T a, T p){return mod_exp(a, p-2, p);}
template <typename T> T exp(T b, T p){T x = 1;while(p){if(p&1)x=(x*b);b=(b*b);p=p<<1;}return x;}
void si(int &x){
register int c = gc();
x = 0;
int neg = 0;
for(;((c<48 || c>57) && c != '-');c = gc());
if(c=='-') {neg=1;c=gc();}
for(;c>47 && c<58;c = gc()) {x = (x<<1) + (x<<3) + c - 48;}
if(neg) x=-x;
}
const int MAXN = (int)1e4+5;
ll BIT[MAXN];
int n;
void update(int idx, int val){
while(idx <= MAXN){
BIT[idx] += val;
idx += idx&-idx;
}
}
ll query(int idx>{
ll sum = 0;
while(idx > 0){
sum += BIT[idx];
idx -= idx&-idx;
}
return sum;
}
ll RSQ(int l, int r){
return query(r) - query(l-1);
}
int main(){
io;
int t;
cin >> t;
while(t--){
int u;
cin >> n >> u;
FOR(i, u){
int l, r;
cin >> l >> r;
++l;++r;
int val;
cin >> val;
update(l, val);
update(r+1, -val);
}
int q;
cin >> q;
while(q--){
int idx;
cin >> idx;
++idx;
cout << query(idx) << endl;
}
memset(BIT, 0, sizeof BIT);
}
return 0;
}
Copy The Code &
Try With Live Editor
Input
5 3
0 1 7
2 4 6
1 3 2
3
0
3
4
Output
8
6
Demonstration
SPOJ Solution-Update the array !-Solution in C, C++, Java, Python