Codeforces Round #281 (Div. 2) 解題報告 A.B.C.D.

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A - Vasya and Football

純類比。。比較坑的是會有不符合足球常識的地方。。

代碼如下：

#include <iostream>#include <cstdio>#include <string>#include <cstring>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <set>#include <algorithm>using namespace std;#define LL __int64const int INF=0x3f3f3f3f;struct node{        int num, time, f;        char ah;}fei[100];int cmp(node x, node y){        return x.time<y.time;}int foul(char c){        if(c=='y') return 1;        return 2;}int main(){        char s1[30], s2[30], c1, c2;        int n, i, j, t, cnt=0, num, flag;        scanf("%s%s",s1,s2);        scanf("%d",&n);        for(i=0;i<n;i++){                scanf("%d %c %d %c",&t,&c1,&num,&c2);                flag=0;                for(j=0;j<cnt;j++){                        if(fei[j].ah==c1&&fei[j].num==num) {                                fei[j].f+=foul(c2);                                if(fei[j].f-foul(c2)<2)                                fei[j].time=t;                                flag=1;                                break;                        }                }                if(!flag){                        fei[cnt].num=num;                        fei[cnt].time=t;                        fei[cnt].ah=c1;                        fei[cnt++].f=foul(c2);                }        }        sort(fei,fei+cnt,cmp);        for(i=0;i<cnt;i++){                if(fei[i].f>=2){                        if(fei[i].ah=='h') printf("%s ",s1);                        else printf("%s ",s2);                        printf("%d %d\n",fei[i].num,fei[i].time);                }        }        return 0;}

B - Vasya and Wrestling

水題。。先比較和然後再根據題意比較字典序即可。實在沒啥好說的。。

代碼如下：

#include <iostream>#include <cstdio>#include <string>#include <cstring>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <set>#include <algorithm>using namespace std;#define LL __int64const int INF=0x3f3f3f3f;LL a[210000], b[210000];int main(){        LL cnt1=0, cnt2=0, n, x, s1=0, s2=0, t;        int i;        scanf("%I64d",&n);        while(n--){                scanf("%I64d",&x);                if(x>0){                        a[cnt1++]=x;                        s1+=x;                }                else{                        b[cnt2++]=-x;                        s2-=x;                }                if(n==0) t=x>0?1:2;        }        if(s1>s2) printf("first\n");        else if(s1<s2) printf("second\n");        else{                int flag=0;                for(i=0;i<cnt1&&i<cnt2;i++){                        if(a[i]>b[i]){                                flag=1;                                break;                        }                        else if(a[i]<b[i]){                                flag=2;                                break;                        }                }                if(flag==1) puts("first");                else if(flag==2) puts("second");                else if(cnt1>cnt2) puts("first");                else if(cnt1<cnt2) puts("second");                else if(t==1) puts("first");                else puts("second");        }        return 0;}

C - Vasya and Basketball

也是一水題。。不過我直接跪了。。各種細節手殘。。居然錯了11次。。。。。中間還交到D題去了一次。。。

先把各種出現過的數存起來，排序，然後分別二分判斷兩人有多少個二分，有多少三分的，找最大值即可。

代碼如下：

#include <iostream>#include <cstdio>#include <string>#include <cstring>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <set>#include <algorithm>using namespace std;#define LL __int64const int INF=0x3f3f3f3f;int a[210000], b[210000], n, m, c[420000], f[420000];int bin_search(int d[], int x, int high){        int low=1, mid, ans=0;        while(low<=high) {                mid=low+high>>1;                if(d[mid]<=x) {                        ans=mid;                        low=mid+1;                }                else high=mid-1;        }        return ans;}int main(){        int i, j, aa, bb, max1=-2*1e9, x, y, z, cnt=1, p1, p2;        scanf("%d",&n);        for(i=1; i<=n; i++) {                scanf("%d",&a[i]);                c[i]=a[i];        }        scanf("%d",&m);        for(i=1; i<=m; i++) {                scanf("%d",&b[i]);                c[i+n]=b[i];        }        sort(c+1,c+n+m+1);        sort(a+1,a+n+1);        sort(b+1,b+m+1);        c[0]=0;        f[0]=0;        for(i=1;i<=n+m;i++){                if(c[i]!=c[i-1]){                        f[cnt++]=c[i];                }        }        for(i=0;i<cnt;i++){                x=bin_search(a,f[i],n);                y=bin_search(b,f[i],m);                p1=x*2+(n-x)*3;                p2=y*2+(m-y)*3;                                if(max1<p1-p2){                        max1=p1-p2;                        aa=p1;                        bb=p2;                }        }        printf("%d:%d\n",aa,bb);        return 0;}

D - Vasya and Chess

猜想題、、所以我是猜的、、證明不會。。

代碼如下：

#include <iostream>#include <cstdio>#include <string>#include <cstring>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <set>#include <algorithm>using namespace std;#define LL __int64const int INF=0x3f3f3f3f;int main(){        int n;        scanf("%d",&n);        if(n%2==0)  printf("white\n1 2\n");        else                printf("black\n");        return 0;}

Codeforces Round #281 (Div. 2) 解題報告 A.B.C.D.