1.29 CF edu103
A题:
容斥原理直接除就行;
代码:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include<bits/stdc++.h> 2 #define ll long long 3 using namespace std; 4 int main(){ 5 int T; 6 scanf("%d",&T); 7 while (T--){ 8 ll n,k; 9 scanf("%lld%lld",&n,&k); 10 ll cmp=k; 11 while (cmp<n){ 12 cmp+=k; 13 } 14 ll res=(cmp+n-1)/n; 15 printf("%lld\n",res); 16 } 17 }
B题:
从后往前推一遍,保证小于k%就行。
代码:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include<bits/stdc++.h> 2 #define ll long long 3 using namespace std; 4 ll a[105],n,k; 5 int main(){ 6 int T; 7 scanf("%d",&T); 8 while (T--){ 9 scanf("%lld%lld",&n,&k); 10 ll sum=0; 11 for (int i=1; i<=n; i++){ 12 scanf("%lld",&a[i]); 13 sum+=a[i]; 14 } 15 ll ret=0; 16 for (int i=n; i>=2; i--){ 17 sum-=a[i]; 18 if (100*a[i]>k*sum){ 19 ll add; 20 if (100*a[i]%k==0) 21 add=100*a[i]/k-sum; 22 else add=100*a[i]/k-sum+1; 23 ret+=add; 24 sum+=add; 25 } 26 } 27 printf("%lld\n",ret); 28 } 29 }
C题:
DP,从后往前,每次选一下是只要两个还是加上之前做出来的最优解。
代码:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include<bits/stdc++.h> 2 #define ll long long 3 using namespace std; 4 ll n,a[100005],b[100005],c[100005],d[100005],sum[100005]; 5 ll dp[100005]; 6 int main(){ 7 int T; 8 scanf("%d",&T); 9 while (T--){ 10 scanf("%lld",&n); 11 for (int i=1; i<=n; i++) 12 scanf("%lld",&a[i]); 13 for (int i=1; i<=n; i++) 14 scanf("%lld",&b[i]); 15 for (int i=1; i<=n; i++) 16 scanf("%lld",&c[i]); 17 for (int i=1; i<n; i++){ 18 d[i]=abs(b[i+1]-c[i+1])+1; 19 } 20 dp[n-1]=d[n-1]+a[n]; 21 for (int i=n-2; i>=1; i--){ 22 dp[i]=d[i]+a[i+1]; 23 if (d[i+1]!=1){ 24 dp[i]=max(d[i]+min(c[i+2],b[i+2])+a[i+1]-max(c[i+2],b[i+2])+1+dp[i+1]-d[i+1],dp[i]); 25 } 26 } 27 ll ret=0; 28 for (int i=1; i<=n-1; i++) 29 ret=max(ret,dp[i]); 30 printf("%lld\n",ret); 31 } 32 }
D题:
打的时候感觉是个记忆化,可惜写挂了,没时间改,之后别人告诉我递推也能过(当然记忆化也行),之后赶紧补一下。
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include<bits/stdc++.h> 2 using namespace std; 3 int st[300005],ed[300005],res[300005]; 4 char s[300005]; 5 int n; 6 int main(){ 7 int T; 8 scanf("%d",&T); 9 while (T--){ 10 scanf("%d",&n); 11 scanf("%s",s+1); 12 st[0]=0; 13 for (int i=1; i<=n; i++){ 14 if (s[i]=='L'){ 15 if (i==1) st[i]=st[i-1]+1; 16 else if (st[i-1]==0){ 17 st[i]=st[i-2]+2; 18 } 19 else st[i]=1; 20 } 21 else { 22 st[i]=0; 23 } 24 } 25 ed[n]=0; 26 for (int i=n-1; i>=0; i--){ 27 if (s[i+1]=='R'){ 28 if (i==n-1) ed[i]=ed[i+1]+1; 29 else if (ed[i+1]==0){ 30 ed[i]=ed[i+2]+2; 31 } 32 else ed[i]=1; 33 } 34 else { 35 ed[i]=0; 36 } 37 } 38 for (int i=0; i<=n; i++) 39 printf("%d ",ed[i]+1+st[i]); 40 printf("\n"); 41 } 42 return 0; 43 }
(连打两场CF状态真的很差,前一天上的分全还回去[叹气]