EDU Two Pointers Method step 3

Revision en7, by SeniorBOTx, 2022-05-16 20:37:42

In step 3 , question number 1 : I write two codes very similar to each , As i am a newbie can you help me out to find what is difference in two code. I got ac in one submission and wrong answer in other.

Also if you don not know what difference between two code, give this blog a upvote so many people can see it.

[problem:307094A]

AC : [submission:157416384]

WA : [submission:157415655]

void solve()
{
int n, p; cin >> n >> p;
int sum{}, ans = 0 , res{}, index{}, prefix{};

vector<int> v(2 * n);
rep(i, 0, n) {
cin >> v[i];
v[i + n] = v[i];
sum += v[i];
}

if (sum < p) {
res = p / sum * n;
p %= sum;
}
if (p != 0) {
ans = INT_MAX;
for (int r = 0, l = 0; r < 2 * n ; r++ ) {
prefix += v[r];
while (l < n and prefix >= p) {
if (ans > r - l + 1) {
ans = r - l + 1;
index = l ;
}
prefix -= v[l];
l++;
}
}
}
cout << index + 1 << " " << ans  + res << endl;

}


WA :

void solve()
{
int n, p; cin >> n >> p;
int sum{}, ans = LLONG_MAX , res{}, index{}, prefix{};

vector<int> v(2 * n);
rep(i, 0, n) {
cin >> v[i];
v[i + n] = v[i];
sum += v[i];
}

if (sum < p) {
res = p / sum * n;
p %= sum;
}

for (int r = 0, l = 0; r < 2 * n ; r++ ) {
prefix += v[r];
while (l < n and prefix >= p) {
if (ans > r - l + 1) {
ans = r - l + 1;
index = l + 1;
}
prefix -= v[l]; l++;
}
}

cout << index << " " << ans  + res << endl;

}


[meanwhile this is my first time here]

#### History

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en7 SeniorBOTx 2022-05-16 20:37:42 8
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en4 SeniorBOTx 2022-05-16 20:34:23 12
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en1 SeniorBOTx 2022-05-16 20:30:59 2901 Initial revision (published)