# Sum of two values CSES

Hi,

I am currently working on Sum of Two values, and I am not sure when to increment i and j in the while loop. I tried to do a for loop, but it gave me a time limit error.

This is my code:
#include <bits/stdc++.h>
using namespace std;

``````#define setIO() ios_base::sync_with_stdio(false); cin.tie(NULL);

const int MAX_N = 2e5;
int num_of_numbers = 0;
int desired_sum = 0;
unsigned long numbers[MAX_N];

void solve() {
setIO();
cin >> num_of_numbers;
cin >> desired_sum;
vector<pair<int, int>> ans;

for (int i = 0; i < num_of_numbers; i++) {
cin >> numbers[i];
}

for (int i = 0; i < num_of_numbers; i++) {
for (int j = i + 1; j < num_of_numbers; j++) {
if (numbers[i] + numbers[j] == desired_sum) {
ans.push_back(make_pair(i + 1, j + 1));
break;
}
}
}

if (ans.size() >= 1) {
cout << ans.first << " " << ans.second << endl;
} else {
cout << "IMPOSSIBLE" << endl;
}
}

void solve_optimized() {
setIO();
cin >> num_of_numbers;
cin >> desired_sum;
vector<pair<int, int>> ans;

for (int i = 0; i < num_of_numbers; i++) {
cin >> numbers[i];
}

sort(numbers, numbers + num_of_numbers);
int i = 0;
int j = i + 1;

while (i < num_of_numbers && j < num_of_numbers) {
if (numbers[i] + numbers[j] == desired_sum) {
ans.push_back(make_pair(i + 1, j + 1));
i++;
j++;
break;
}

else if (numbers[i] + numbers[j] < desired_sum) {
j++;
}

else {
i++;
}
}

if (ans.size() >= 1) {
cout << ans.first << " " << ans.second << endl;
} else {
cout << "IMPOSSIBLE" << endl;
}
}

int main() {
solve_optimized();
}
``````

Note: solve - for loop
solve_optimized - while loop

Again, try and calculate the complexity of your code and see if it should or shouldn’t TLE.

it dosent tle, it just gives a wrong answer, but I am not sure how to fix it.

yeah, but I dont get how to fix it…

Is it because the test cases are too large?

ya, mostly all of the test cases that are too large are either getting tle or wrong answer…

Step 1:
Iterate through the numbers, and try to find the sum. If it does, then add it to the pair.

Step 2:
If J is at the end of the numbers, add 1 to i

Step 3:
if none of these conditions are satisfied, Add 1 to J

this is the algorithm i am following

Updated code:
#include <bits/stdc++.h>
using namespace std;

``````#define setIO() ios_base::sync_with_stdio(false); cin.tie(NULL);

const int MAX_N = 2e5;
int num_of_numbers = 0;
int desired_sum = 0;
unsigned long numbers[MAX_N];

void solve() {
setIO();
cin >> num_of_numbers;
cin >> desired_sum;
vector<pair<int, int>> ans;

for (int i = 0; i < num_of_numbers; i++) {
cin >> numbers[i];
}

for (int i = 0; i < num_of_numbers; i++) {
for (int j = i + 1; j < num_of_numbers; j++) {
if (numbers[i] + numbers[j] == desired_sum) {
ans.push_back(make_pair(i + 1, j + 1));
break;
}
}
}

if (ans.size() >= 1) {
cout << ans.first << " " << ans.second << endl;
} else {
cout << "IMPOSSIBLE" << endl;
}
}

void solve_optimized() {
setIO();
cin >> num_of_numbers;
cin >> desired_sum;
int a = 0, b = 0;
vector<pair<int, int>> ans;

for (int i = 0; i < num_of_numbers; i++) {
cin >> numbers[i];
}

// sort(numbers, numbers + num_of_numbers);
int i = 0;
int j = i + 1;

while (i < num_of_numbers && j < num_of_numbers) {
if (numbers[i] + numbers[j] == desired_sum) {
// ans.push_back(make_pair(i + 1, j + 1));
a = i + 1;
b = j + 1;
i++;
j++;
break;
}
else {
if (j == num_of_numbers - 1) {
i++;
j = i + 1;
}
else
j++;
}

/*
else {
i++;
}
*/
}

if ((a != 0) && (b != 0)) {
cout << a << " " << b << endl;
} else {
cout << "IMPOSSIBLE" << endl;
}
}

int main() {
solve_optimized();
}``````