fork download
copy 
  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define int              long long int
  4. #define double           long double
  5. #define print(a)         for(auto x : a) cout << x << " "; cout << endl
  6.  
  7.  
  8. const int M = 1000000007;
  9. const int N = 3e5+9;
  10. const int INF = 2e9+1;
  11. const int LINF = 2000000000000000001;
  12.  
  13. inline int power(int a, int b, int mod=M) {
  14.     int x = 1;
  15.     a %= mod;
  16.     while (b) {
  17.         if (b & 1) x = (x * a) % mod; 
  18.         a = (a * a) % mod;
  19.         b >>= 1;
  20.     }
  21.     return x;
  22. }
  23.  
  24.  
  25. //_ ***************************** START Below *******************************
  26.  
  27. // 3
  28. // 5
  29. // 0 0 0 0 0 
  30. // 12
  31. // 2 -3 6 0 4 -5 6 0 2 3 4 1
  32. // 11
  33. // 8 -3 1 -6 4 -4 7 -7 2 -2 0
  34.  
  35.  
  36.  
  37.  
  38.  
  39. vector<int> a;
  40.  
  41.  
  42. int consistency1(int n){
  43.  
  44. 	int total = 0;
  45. 	for(int i=0; i<n; i++) total += a[i];
  46.  
  47. 	if(total % 4 != 0) return false;
  48. 	int x = total/4;
  49.  
  50. 	unordered_map<int,int> prefixSum, suffixSum;
  51.  
  52. 	int sum = 0;
  53. 	for(int i=n-1; i>=0; i--){
  54. 		sum += a[i];
  55. 		suffixSum[sum]++;
  56. 	}
  57.  
  58.  
  59. 	int ans = 0;
  60. 	int leftSum = 0;
  61. 	int rightSum = total;
  62.  
  63.  
  64. 	for(int i=0; i<=n-2; i++){
  65. 		suffixSum[rightSum]--;
  66. 		if(suffixSum[rightSum] == 0) suffixSum.erase(rightSum);
  67.  
  68. 		leftSum += a[i];
  69. 		rightSum -= a[i];
  70.  
  71.  
  72. 		suffixSum[rightSum]--;
  73.  
  74.  
  75. 		if(leftSum == 2*x){
  76. 			ans += prefixSum[leftSum/2] * suffixSum[rightSum/2];
  77. 		}
  78.  
  79. 		suffixSum[rightSum]++;
  80. 		prefixSum[leftSum]++;
  81. 	}
  82.  
  83. 	return ans;
  84.  
  85. }
  86.  
  87.  
  88.  
  89.  
  90.  
  91. int consistency2(int n){
  92.  
  93. 	int total = 0;
  94. 	for(int i=0; i<n; i++) total += a[i];
  95.  
  96. 	if(total % 4 != 0) return 0;
  97.  
  98. 	int x = total/4;
  99.  
  100. 	vector<int> suffixWays(n, 0);
  101. 	int ct_x = 0;
  102. 	int sum = 0;
  103.  
  104. 	for(int i=n-1; i>=0; i--){
  105. 		sum += a[i];
  106.  
  107. 		if(sum == 2*x){
  108. 			suffixWays[i] += ct_x; 
  109. 		}		
  110. 		if(sum == x){
  111. 			ct_x++;
  112. 		}
  113. 	}
  114.  
  115.  
  116. 	sum = 0;
  117. 	ct_x = 0;
  118. 	int ans = 0;
  119.  
  120. 	for(int i=0; i<=n-3; i++){
  121. 		sum += a[i];
  122. 		if(sum == 2*x)	ans += ct_x * suffixWays[i+1];
  123.  
  124. 		if(sum == x) ct_x++;
  125. 	}
  126.  
  127.  
  128.     return ans;
  129. }
  130.  
  131.  
  132.  
  133.  
  134.  
  135.  
  136.  
  137.  
  138.  
  139.  
  140.  
  141.  
  142.  
  143.  
  144.  
  145.  
  146.  
  147.  
  148.  
  149.  
  150.  
  151.  
  152.  
  153. int practice(int n){
  154.  
  155.  
  156. }
  157.  
  158.  
  159.  
  160.  
  161.  
  162. void solve() {
  163.  
  164.     int n;
  165.     cin>> n;
  166.  
  167.     a.resize(n);
  168.     for(int i=0; i<n; i++) cin >> a[i];
  169.  
  170.     cout << consistency1(n) << " " << consistency2(n) << endl;
  171.  
  172.     // cout << practice(n) << endl;
  173.  
  174.  
  175. }
  176.  
  177.  
  178.  
  179.  
  180.  
  181. int32_t main() {
  182.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  183.  
  184.     int t = 1;
  185.     cin >> t;
  186.     while (t--) {
  187.         solve();
  188.     }
  189.  
  190.     return 0;
  191. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin
copy 
3
5
0 0 0 0 0 
12
2 -3 6 0 4 -5 6 0 2 3 4 1
11
8 -3 1 -6 4 -4 7 -7 2 -2 0
stdout
copy 
4 4
4 4
4 4
https://ideone.com/lEYbff
language:
C++14 (gcc 8.3)
created:
4 days ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!