Problem Statement
Given is a string SS consisting of digits from 1
through 9
.
Find the number of pairs of integers (i,j)(i,j) (1≤i≤j≤|S|1≤i≤j≤|S|) that satisfy the following condition:
Condition: In base ten, the ii-th through jj-th characters of SS form an integer that is a multiple of 20192019.
Constraints
- 1≤|S|≤2000001≤|S|≤200000
-
SS is a string consisting of digits from
1
through9
.
Input
Input is given from Standard Input in the following format:
SS
Output
Print the number of pairs of integers (i,j)(i,j) (1≤i≤j≤|S|1≤i≤j≤|S|) that satisfy the condition.
Sample Input 1 Copy
Copy1817181712114
Sample Output 1 Copy
Copy3
Three pairs - (1,5)(1,5), (5,9)(5,9), and (9,13)(9,13) - satisfy the condition.
Sample Input 2 Copy
Copy14282668646
Sample Output 2 Copy
Copy2
Sample Input 3 Copy
Copy2119
Sample Output 3 Copy
Copy0
No pairs satisfy the condition.
若 i到j 满足要求,
则2019|s[0,j]-s[0,i],
有s[0,j]%2019=s[0,i]%2019
#include <iostream> #include <vector> #include <algorithm> #include <string> #include <set> #include <queue> #include <map> #include <sstream> #include <cstdio> #include <cstring> #include <numeric> #include <cmath> #include <iomanip> #include <deque> #include <bitset> #define ll long long #define PII pair<int, int> #define rep(i,a,b) for(int i=a;i<=b;i++) #define dec(i,a,b) for(int i=a;i>=b;i--) #define pb push_back #define mk make_pair using namespace std; int dir[4][2] = { { 0,1 } ,{ 0,-1 },{ 1,0 },{ -1,0 } }; const long long INF = 0x7f7f7f7f7f7f7f7f; const int inf = 0x3f3f3f3f; const double pi = 3.14159265358979323846; const int mod = 998244353; const int N = 50 + 5; //if(x<0 || x>=r || y<0 || y>=c) inline ll read() { ll x = 0; bool f = true; char c = getchar(); while (c < '0' || c > '9') { if (c == '-') f = false; c = getchar(); } while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); return f ? x : -x; } ll gcd(ll m, ll n) { return n == 0 ? m : gcd(n, m % n); } ll lcm(ll m, ll n) { return m * n / gcd(m, n); } int main() { string s; cin >> s; map<int, int> mp; mp[0] = 1; int x = 0, ans = 0, cnt = 1; for (int i = s.size()-1; i >=0 ; i--) { x = ((s[i] - '0')*cnt + x)%2019; ans += mp[x]; mp[x]++; cnt = cnt * 10 % 2019; } cout << ans << endl; return 0; }