第十七周 12.20-12.26
12.20-12.22
什么都没做。
12.23
POJ 3581 Sequence
这是一个单case过EOF哇的神题。我只是想验个板阿QAQ。
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <algorithm> 5 using namespace std; 6 const int maxn = 1e6 + 10; 7 8 int s[maxn], rev[maxn]; 9 int n, k, SA[maxn], r[maxn], tmp[maxn]; 10 bool cmp(int i, int j) 11 { 12 if(r[i] != r[j]) return r[i] < r[j]; 13 return ( i + k <= n ? r[i+k] : -1 ) < ( j + k <= n ? r[j+k] : -1 ); 14 } 15 void get_SA(int sz) 16 { 17 for(int i = 0; i <= sz; i++) 18 { 19 SA[i] = i; 20 r[i] = i < sz ? rev[i] : -1; 21 } 22 for(k = 1; k <= sz; k <<= 1) 23 { 24 sort(SA, SA + sz + 1, cmp); 25 tmp[SA[0]] = 0; 26 for(int i = 1; i <= sz; i++) tmp[SA[i]] = tmp[SA[i-1]] + cmp(SA[i-1], SA[i]); 27 memcpy(r, tmp, sizeof(r)); 28 } 29 return; 30 } 31 32 void R(int * t, int l, int r) 33 { 34 for(int i = 0; i <= (r - l) / 2; i++) swap(t[l+i], t[r-i]); 35 } 36 37 int main(void) 38 { 39 scanf("%d", &n); 40 int p1, p2; 41 for(int i = 0; i < n; i++) scanf("%d", s + i); 42 memcpy(rev, s, sizeof(rev)); 43 R(rev, 0, n - 1); 44 get_SA(n); 45 for(int i = 0; i <= n; i++) 46 if(SA[i] > 1 && SA[i] < n) 47 {p1 = n - SA[i]; break;} 48 int m = n - p1; 49 for(int i = 0; i < m; i++) rev[i] = rev[i + m] = s[p1 + i]; 50 R(rev, 0, 2 * m - 1); 51 get_SA(2 * m); 52 for(int i = 0; i <= 2 * m; i++) 53 { 54 p2 = p1 + m - SA[i]; 55 if(p2 > p1 && p2 < n) break; 56 } 57 R(s, 0, p1 - 1); 58 R(s, p1, p2 - 1); 59 R(s, p2, n - 1); 60 for(int i = 0; i < n; i++) printf("%d\n", s[i]); 61 return 0; 62 }
12.24
补个CF。
CF 608 C Chain Reaction
dp推。
1 #include <iostream> 2 #include <cstdio> 3 #include <algorithm> 4 using namespace std; 5 const int maxn = 1e6 + 10; 6 int pos[maxn], level[maxn]; 7 int dp[maxn]; 8 9 int main(void) 10 { 11 int n; 12 scanf("%d", &n); 13 for(int i = 1; i <= n; i++) 14 { 15 int a, b; 16 scanf("%d%d", &a, &b); 17 pos[a] = 1; 18 level[a] = b; 19 } 20 int ans = 0; 21 for(int i = 0; i < maxn; i++) 22 { 23 if(!pos[i]) dp[i+1] = dp[i]; 24 else dp[i+1] = (i - level[i] >= 0 ? dp[i-level[i]] : 0 ) + 1; 25 ans = max(ans, dp[i+1]); 26 } 27 printf("%d\n",n - ans); 28 return 0; 29 }
CF 608 D Zuma
不会捉。
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 using namespace std; 5 int c[555], dp[555][555]; 6 7 int main(void) 8 { 9 int n; 10 scanf("%d", &n); 11 for(int i = 1; i <= n; i++) scanf("%d", c + i); 12 for(int i = 1; i <= n; i++) 13 for(int j = i; j <= n; j++) 14 dp[i][j] = (i == j ? 1 : n + 1 ); 15 for(int l = 2; l <= n; l++) 16 { 17 for(int s = 1; s + l - 1 <= n; s++) 18 { 19 for(int k = s; k < s + l - 1; k++) 20 dp[s][s+l-1] = min(dp[s][s+l-1], dp[s][k] + dp[k+1][s+l-1]); 21 if(c[s] == c[s+l-1]) dp[s][s+l-1] = max(1, min(dp[s][s+l-1],dp[s+1][s+l-2])); 22 } 23 } 24 printf("%d\n", dp[1][n]); 25 return 0; 26 }
CF 608 E Marbles
不懂证。
1 #include <iostream> 2 #include <cstdio> 3 #include <algorithm> 4 using namespace std; 5 const int maxn = 1e6 + 10; 6 int n, Next[maxn]; 7 char a[maxn], b[maxn]; 8 9 void getNext(void) 10 { 11 Next[0] = Next[1] = 0; 12 for(int i = 1; i < n; i++) 13 { 14 int j = Next[i]; 15 while( j && b[i] != b[j]) j = Next[j]; 16 Next[i+1] = b[i] == b[j] ? j + 1 : 0; 17 } 18 return; 19 } 20 21 bool KMP(void) 22 { 23 getNext(); 24 int j = 0; 25 for(int i = 0; i < n; i++) 26 { 27 while(j && b[j] != a[i]) j = Next[j]; 28 if(b[j] == a[i]) j++; 29 if(i == n - 1 && j) return true; 30 } 31 return false; 32 } 33 34 int main(void) 35 { 36 scanf("%d", &n); 37 n--; 38 scanf("%s%s", a, b); 39 for(int i = 0; i < n; i++) 40 { 41 if(b[i] == 'N') b[i] = 'S'; 42 else if(b[i] == 'S') b[i] = 'N'; 43 else if(b[i] == 'E') b[i] = 'W'; 44 else b[i] = 'E'; 45 } 46 reverse(b, b + n); 47 puts(KMP() ? "NO" : "YES"); 48 return 0; 49 }
12.25-12.26
什么都没干。
