The first question of the second online programming challenge monthly competition of the Ares cup: The number of replies

Question details:

Njzy learns the return string and then associates it with the return number. He wants to count all the return numbers in a range. Given a closed interval [a, B], calculate the number of replies in this interval.

For example, [20, 30], there is only one input number, which is 22.

 

Input description:

The input includes multiple groups of test data. Each group of test data includes two integers, A and B,

(0 <A <= B <10 ^ 6 ).

Output description:

Output the corresponding answer for each group of trial data.

 

Q & A description:

Input example:

1

10

20

30

300

400

Output example:

9

1

10

Solution:

Total [I] indicates the number of replies between 1 and I. After preprocessing, the number of replies between A and B is required, directly output total [B]-total [A-1. The first time this question was submitted, it was a tragedy because the array had crossed the border.

Const int maxn = 1000000 + 10; int total [maxn], after preprocessing the total array, from 1 to maxn, out of bounds, the maximum array subscript is maxn-1, ah, tragedy.

ASIDE: this month, I wrote very few blog posts and was busy reviewing the final exam. I had to raise my score.

Code:

# Include <iostream> # include <string. h> using namespace STD; const int maxn = 1000000; int num [10]; int total [maxn + 10]; // total [I] indicates the number of replies between 1 and I. bool Pd (INT N) // determines whether it is the number of replies {int K = 0; int temp = N; while (temp) {num [++ K] = TEMP % 10; temp/= 10;} For (INT I = 1; I <= K/2; I ++) {If (Num [I]! = Num [k-I + 1]) return false;} return true;} void CAL (int n) // preprocessing total [I] {int K = 0; for (INT I = 1; I <= N; I ++) {If (Pd (I) K ++; Total [I] = K ;}} int main () {total [0] = 0; CAL (maxn); int A, B; while (CIN> A> B) {cout <total [B]-total [A-1] <Endl;} return 0 ;}

Later, I can see on the Internet whether it is a better function for people to infer the number of replies:

For example:

Bool Pd (int n) // infer whether it is the number of input files {int temp = N; int m = 0; while (temp) {M = m * 10 + TEMP % 10; // The Reverse Order of M is n temp/= 10;} return n = m ;}

The first question of the second online programming challenge monthly competition of the Ares cup: The number of replies