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  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.  
  28.  
  29.  
  30. vector<int> a;
  31.  
  32. int consistency1(int n){
  33. 	if(n==1) return -INF;
  34. 	if(n==2 && a[0]>a[1]) return 1;
  35. 	else if(n==2) return -INF;
  36.  
  37. 	vector<int> dp(n+1, -INF);
  38. 	dp[0] = 0;
  39.  
  40. 	dp[1] = -INF;
  41. 	if(a[0] > a[1] ) dp[2] = 1; 
  42.  
  43. 	for(int i=3; i<=n; i++){
  44.  
  45. 		int j = i-2;
  46. 		int maxi = a[i-1];
  47. 		int maxI = i-1;
  48. 		if(a[i-2]>maxi){
  49. 			maxi = a[i-2];
  50. 			maxI = i-2;
  51. 		}
  52.  
  53. 		while(j>=0){
  54.  
  55. 			if(dp[j] != -INF && maxI != i-1)	dp[i] = max(dp[i], dp[j]+1);
  56.  
  57. 			if(j-1>=0){
  58. 				if(a[j-1] > maxi){
  59. 					maxi = a[j-1];
  60. 					maxI = j-1;
  61. 				}
  62. 			}
  63. 			j--;
  64. 		}
  65. 	}
  66.  
  67. 	return dp[n];
  68. }
  69.  
  70.  
  71.  
  72.  
  73.  
  74.  
  75.  
  76.  
  77. int consistency2(int n){
  78. 	if(n==1) return -INF;
  79. 	if(n==2 && a[0]>a[1]) return 1;
  80. 	else if(n==2) return -INF;
  81.  
  82. 	vector<int> pge(n, -1);
  83. 	stack<int> st;
  84. 	for(int i=n-1; i>=0; i--){
  85. 		while(!st.empty() && a[i] > a[st.top()] ){
  86. 			auto top = st.top();	st.pop();
  87. 			pge[top] = i;
  88. 		}
  89. 		st.push(i);
  90. 	}
  91.  
  92.  
  93. 	vector<int> dp(n+1, -INF);
  94. 	vector<int> dpMaxi(n+1, -INF);
  95. 	dp[0] = 0;
  96. 	dpMaxi[0] = 0;
  97.  
  98. 	dp[1] = -INF;
  99. 	dpMaxi[1] = max(dpMaxi[0], dp[1]);
  100.  
  101. 	if(a[0] > a[1] ) dp[2] = 1; 
  102. 	dpMaxi[2] = max(dpMaxi[1], dp[2]);
  103.  
  104. 	for(int i=3; i<=n; i++){
  105.  
  106. 		int maxi = a[i-1];
  107. 		int maxI = i-1;
  108. 		if(a[i-2]>maxi){
  109. 			maxi = a[i-2];
  110. 			maxI = i-2;
  111. 		}
  112.  
  113. 		int j = pge[i-1];
  114. 		if( j!=-1 && dpMaxi[j] != -INF ) 	dp[i] = dpMaxi[j] + 1;
  115. 		dpMaxi[i] = max(dpMaxi[i-1], dp[i]);
  116.  
  117. 	}
  118.  
  119. 	return dp[n];
  120. }
  121.  
  122.  
  123.  
  124.  
  125.  
  126.  
  127.  
  128.  
  129.  
  130.  
  131.  
  132.  
  133.  
  134.  
  135.  
  136. int practice(int n){
  137.  
  138.  
  139.     return 0;
  140. }
  141.  
  142.  
  143.  
  144.  
  145.  
  146. void solve() {
  147.  
  148.     int n;
  149.     cin>> n;
  150.  
  151.     a.resize(n);
  152.     for(int i=0; i<n; i++) cin >> a[i];
  153.  
  154.     cout << consistency1(n) << " " << consistency2(n) << endl;
  155.     // cout << consistency1(n) << endl;
  156.  
  157.  
  158. }
  159.  
  160.  
  161.  
  162.  
  163.  
  164. int32_t main() {
  165.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  166.  
  167.     int t = 1;
  168.     // cin >> t;
  169.     while (t--) {
  170.         solve();
  171.     }
  172.  
  173.     return 0;
  174. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/fpXHjF
language:
C++14 (gcc 8.3)
created:
19 hours ago
visibility:
public

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