CF #283 div2
2014-12-18 13:40:50
思路：前三题敲慢了...导致D时间不足。
A：暴力枚举。
1 #include <cstdio> 2 #include <cstring> 3 #include <cstdlib> 4 #include <cmath> 5 #include <vector> 6 #include <map> 7 #include <set> 8 #include <stack> 9 #include <queue> 10 #include <iostream> 11 #include <algorithm> 12 using namespace std; 13 #define lp (p << 1) 14 #define rp (p << 1|1) 15 #define getmid(l,r) (l + (r - l) / 2) 16 #define MP(a,b) make_pair(a,b) 17 typedef long long ll; 18 typedef unsigned long long ull; 19 const int INF = 1 << 30; 20 21 int n; 22 int a[110]; 23 int ans = INF; 24 25 int main(){ 26 scanf("%d",&n); 27 for(int i = 1; i <= n; ++i) scanf("%d",a + i); 28 sort(a + 1,a + n + 1); 29 for(int i = 2; i < n; ++i){ 30 int d = 0; 31 for(int j = 2; j <= n; ++j){ 32 if(j == i){ 33 d = max(d,a[j + 1] - a[j - 1]); 34 ++j; 35 } 36 else d = max(d,a[j] - a[j - 1]); 37 } 38 ans = min(ans,d); 39 } 40 printf("%d\n",ans); 41 return 0; 42 }
B：暴力枚举哪一位置零。
1 #include <cstdio> 2 #include <cstring> 3 #include <cstdlib> 4 #include <cmath> 5 #include <vector> 6 #include <map> 7 #include <set> 8 #include <stack> 9 #include <queue> 10 #include <iostream> 11 #include <algorithm> 12 using namespace std; 13 #define lp (p << 1) 14 #define rp (p << 1|1) 15 #define getmid(l,r) (l + (r - l) / 2) 16 #define MP(a,b) make_pair(a,b) 17 typedef long long ll; 18 typedef unsigned long long ull; 19 const int INF = 1 << 30; 20 21 int n; 22 char v[1010]; 23 char ans[1010]; 24 char tmp[1010]; 25 char tmp2[1010]; 26 27 int main(){ 28 29 scanf("%d",&n); 30 ans[1] = 'a'; 31 scanf("%s",v + 1); 32 for(int i = 1; i <= n; ++i){ 33 int val = 1 + '9' - v[i]; 34 for(int j = 1; j <= n; ++j) tmp[j] = (v[j] - '0' + val) % 10 + '0'; 35 int pos = i; 36 for(int j = 1; j <= n; ++j){ 37 tmp2[j] = tmp[pos]; 38 pos++; 39 if(pos > n) pos = 1; 40 } 41 if(ans[1] == 'a' || strcmp(tmp2 + 1,ans + 1) < 0) 42 strcpy(ans + 1,tmp2 + 1); 43 } 44 ans[n + 1] = '\0'; 45 printf("%s\n",ans + 1); 46 return 0; 47 }
C：暴力枚举、贪心。
1 #include <cstdio> 2 #include <cstring> 3 #include <cstdlib> 4 #include <cmath> 5 #include <vector> 6 #include <map> 7 #include <set> 8 #include <stack> 9 #include <queue> 10 #include <iostream> 11 #include <algorithm> 12 using namespace std; 13 #define lp (p << 1) 14 #define rp (p << 1|1) 15 #define getmid(l,r) (l + (r - l) / 2) 16 #define MP(a,b) make_pair(a,b) 17 typedef long long ll; 18 typedef unsigned long long ull; 19 const int INF = 1 << 30; 20 21 int n,m,ans,st; 22 int vis[110]; 23 char g[110][110]; 24 25 int main(){ 26 st = 1; 27 ans = 0; 28 scanf("%d%d",&n,&m); 29 for(int i = 0; i < n; ++i) scanf("%s",g[i]); 30 int ans = INF; 31 for(int j = 0; j < m; ++j){ 32 int flag = 1; 33 memset(vis,0,sizeof(vis)); 34 for(int i = 1; i < n; ++i){ 35 if(g[i][j] < g[i - 1][j]){ 36 flag = 0; 37 break; 38 } 39 else if(g[i][j] > g[i - 1][j]) vis[i] = 1; 40 } 41 int res = j; 42 if(flag == 1){ //set j as start 43 for(int k = j + 1; k < m; ++k){ 44 int tag = 1; 45 for(int i = 1; i < n; ++i){ 46 if(g[i][k] < g[i - 1][k] && !vis[i]){ 47 tag = 0; 48 break; 49 } 50 } 51 if(tag){ 52 for(int i = 1; i < n; ++i){ 53 if(g[i][k] > g[i - 1][k]) vis[i] = 1; 54 } 55 } 56 else res += 1; 57 } 58 ans = min(ans,res); 59 } 60 } 61 if(ans >= INF) printf("%d\n",m); 62 else printf("%d\n",ans); 63 return 0; 64 }
D：暴力枚举t，然后二分即可。
1 #include <cstdio> 2 #include <iostream> 3 #include <algorithm> 4 using namespace std; 5 6 int tmp,n,cnt,sum1[100010],sum2[100010]; 7 pair<int,int> ans[100010]; 8 9 int Judge(int t){ 10 int s1 = 0,s2 = 0,c1 = 0,c2 = 0,last; 11 while(1){ 12 int p1 = lower_bound(sum1 + 1,sum1 + n + 1,c1 + t) - sum1; 13 int p2 = lower_bound(sum2 + 1,sum2 + n + 1,c2 + t) - sum2; 14 if(p1 > n && p2 > n) break; 15 if(p2 < p1){ 16 swap(p1,p2); 17 s2++,last = 2; 18 } 19 else s1++,last = 1; 20 c1 = sum1[p1]; 21 c2 = sum2[p1]; 22 } 23 if(c1 + c2 < n || s1 == s2 ||(s1 < s2 && last == 1) ||(s1 > s2 && last == 2)) return 0; 24 return max(s1,s2); 25 } 26 27 int main(){ 28 int v; 29 scanf("%d",&n); 30 for(int i = 1; i <= n; ++i){ 31 scanf("%d",&v); 32 sum1[i] = sum1[i - 1]; 33 sum2[i] = sum2[i - 1]; 34 if(v == 1) sum1[i]++; 35 else sum2[i]++; 36 } 37 for(int t = 1; t <= n; ++t) 38 if(tmp = Judge(t)) ans[++cnt] = make_pair(tmp,t); 39 sort(ans + 1,ans + cnt + 1); 40 printf("%d\n",cnt); 41 for(int i = 1; i <= cnt; ++i) printf("%d %d\n",ans[i].first,ans[i].second); 42 return 0; 43 }
E：贪心，首先按照每个人的highest notes排序，小的在先，（对musical parts也排序），遍历每一个人，然后处理highest notes比他小的所有时间。（当然处理过的parts就不再处理了，就这样扫一遍），用set / sbt 实现（貌似sbt会卡），恩恩。。。考了set成员函数的应用，注意erase函数原理。
1 #include <cstdio> 2 #include <cstring> 3 #include <set> 4 #include <iostream> 5 #include <algorithm> 6 using namespace std; 7 #define MP(a,b) make_pair(a,b) 8 typedef pair<int,int> pii; 9 const int maxn = 100010; 10 11 struct node{ 12 int l,r,id,k; 13 inline void in(){ scanf("%d%d",&l,&r);} 14 friend bool operator < (const node & a,const node &b){ return (a.r == b.r) ? a.l < b.l : a.r < b.r;} 15 }a[maxn],b[maxn]; 16 17 int n,m; 18 int ans[maxn]; 19 set<pii> s; 20 21 int main(){ 22 scanf("%d",&n); 23 for(int i = 1; i <= n; ++i) a[i].in(),a[i].id = i; 24 scanf("%d",&m); 25 for(int i = 1; i <= m; ++i) b[i].in(),b[i].id = i,scanf("%d",&b[i].k); 26 sort(a + 1,a + n + 1),sort(b + 1,b + m + 1); 27 int now = 1; 28 for(int i = 1; i <= m; ++i){ 29 while(now <= n && a[now].r <= b[i].r) s.insert(MP(a[now].l,a[now].id)),now++; 30 int cnt = 0; 31 set<pii>::iterator it = s.lower_bound(MP(b[i].l,0)); 32 while(cnt < b[i].k && it != s.end()){ 33 ans[it->second] = b[i].id; 34 s.erase(it); 35 it++,cnt++; 36 } 37 } 38 if(now >n && s.empty()){ 39 printf("YES\n"); 40 for(int i = 1; i <= n; ++i) printf("%s%d",i == 1 ? "" : " ",ans[i]); 41 puts(""); 42 } 43 else printf("NO\n"); 44 return 0; 45 }
