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还带这么做的，卧槽，15分钟就被A了的题，居然没搞出来
若某位是1，则前两个为wb，这位就是w
1 #include<cstdio> 2 #include<cstring> 3 #define lson l,m,rt<<1 4 #define rson m+1,r,rt<<1|1 5 using namespace std; 6 const int maxn=50010; 7 int n,m,sum[maxn<<2]; 8 char str[maxn]; 9 int num[maxn]; 10 void pushup(int rt) 11 { 12 sum[rt]=sum[rt<<1]+sum[rt<<1|1]; 13 } 14 void build(int l,int r,int rt) 15 { 16 if(l==r) 17 { 18 sum[rt]=num[l]; 19 return; 20 } 21 int m=(l+r)>>1; 22 build(lson); 23 build(rson); 24 pushup(rt); 25 } 26 int query(int L,int R,int l,int r,int rt) 27 { 28 if(L<=l&&r<=R) 29 { 30 return sum[rt]; 31 } 32 int m=(l+r)>>1; 33 int ans=0; 34 if(L<=m) ans+=query(L,R,lson); 35 if(R>m) ans+=query(L,R,rson); 36 return ans; 37 } 38 void update(int p,int val,int l,int r,int rt) 39 { 40 if(l==r) 41 { 42 sum[rt]=val; 43 return; 44 } 45 int m=(l+r)>>1; 46 if(p<=m) update(p,val,lson); 47 else update(p,val,rson); 48 pushup(rt); 49 } 50 int main() 51 { 52 int t,T; 53 scanf("%d",&T); 54 for(int t=1;t<=T;t++) 55 { 56 printf("Case %d:\n",t); 57 scanf("%d%d%s",&n,&m,str+1); 58 memset(num,0,sizeof(num)); 59 for(int i=3;i<=n;i++) 60 if(str[i-2]==‘w‘&&str[i-1]==‘b‘&&str[i]==‘w‘) num[i]=1; 61 build(1,n,1); 62 int k,a,b; 63 char ch[5]; 64 while (m--) 65 { 66 scanf("%d",&k); 67 if(k==0) 68 { 69 scanf("%d%d",&a,&b); 70 a++;b++; //字符串从1开始，所以下标都加1 71 if(b-a<2) printf("0\n"); 72 else printf("%d\n",query(a+2,b,1,n,1)); 73 } 74 else 75 { 76 scanf("%d%s",&a,ch); 77 a++; 78 if(ch[0]==str[a]) continue;//修改的和以前一样，这不用任何操作 79 if(a>=3) 80 { 81 if(str[a-2]==‘w‘&&str[a-1]==‘b‘&&str[a]==‘w‘) 82 update(a,0,1,n,1); 83 if(str[a-2]==‘w‘&&str[a-1]==‘b‘&&str[a]==‘b‘) 84 update(a,1,1,n,1); 85 } 86 if(a>=2&&a+1<=n) 87 { 88 if(str[a-1]==‘w‘&&str[a]==‘b‘&&str[a+1]==‘w‘) 89 update(a+1,0,1,n,1); 90 if(str[a-1]==‘w‘&&str[a]==‘w‘&&str[a+1]==‘w‘) 91 update(a+1,1,1,n,1); 92 } 93 if(a+2<=n) 94 { 95 if(str[a]==‘w‘&&str[a+1]==‘b‘&&str[a+2]==‘w‘) 96 update(a+2,0,1,n,1); 97 if(str[a]==‘b‘&&str[a+1]==‘b‘&&str[a+2]==‘w‘) 98 update(a+2,1,1,n,1); 99 } 100 str[a]=ch[0]; 101 } 102 } 103 } 104 return 0; 105 }
1 #include<cstdio> 2 #include<iostream> 3 #include<algorithm> 4 #include<cstring> 5 #include<cmath> 6 #include<queue> 7 #define lson l,mid,rt<<1 8 #define rson mid+1,r,rt<<1|1 9 #define root 1,n,1 10 #define mid ((l+r)>>1) 11 #define ll long long 12 #define cl(a) memset(a,0,sizeof(a)) 13 #define ts printf("*****\n"); 14 using namespace std; 15 const int MAXN=50010; 16 int sum[MAXN<<2],lsum[MAXN<<2],rsum[MAXN<<2],lc[MAXN<<2],rc[MAXN<<2]; 17 int n,m,tt; 18 char s[MAXN]; 19 void pushup(int l,int r,int rt) 20 { 21 //printf("%d %d %d %d\n",l,r,rt,mid); 22 /*if(mid==3) 23 { 24 printf("%s\n",s+1); 25 printf("%c %c %c\n",s[mid-1],s[mid],s[mid+1]); 26 }*/ 27 sum[rt]=sum[rt<<1]+sum[rt<<1|1]; 28 if(/*(s[mid]==‘b‘&&s[mid-1]==‘w‘&&s[mid+1]==‘w‘)||*/(s[mid]==‘w‘&&s[mid+1]==‘b‘&&s[mid+2]==‘w‘)&&mid+1<=n) 29 { 30 sum[rt]+=1; 31 } 32 } 33 void build(int l,int r,int rt) 34 { 35 if(l==r) 36 { 37 sum[rt]=0; 38 return; 39 } 40 build(lson); 41 build(rson); 42 pushup(l,r,rt); 43 } 44 void update(int pos,int val,int l,int r,int rt) 45 { 46 if(l==r) 47 { 48 return; 49 } 50 update(pos,val,lson); 51 update(pos,val,rson); 52 pushup(l,r,rt); 53 } 54 int query(int L,int R,int l,int r,int rt) 55 { 56 57 //printf("%d %d %d %d %d\n",L,R,l,r,rt); 58 if(L<=l&&r<=R) 59 { 60 return sum[rt]; 61 } 62 if(R<=mid) return query(L,R,lson); 63 if(L>mid) return query(L,R,rson); 64 65 int ta,tb; 66 ta=query(L,R,lson); 67 tb=query(L,R,rson); 68 int ans; 69 ans=max(ta,tb); 70 if(/*(s[mid]==‘b‘&&s[mid-1]==‘w‘&&s[mid+1]==‘w‘)||*/(s[mid]==‘w‘&&s[mid+1]==‘b‘&&s[mid+2]==‘w‘)&&mid+1<=n) //同上 71 { 72 ans+=1; 73 } 74 return ans; 75 } 76 int main() 77 { 78 int i,j,k; 79 #ifndef ONLINE_JUDGE 80 freopen("1.in","r",stdin); 81 #endif 82 scanf("%d",&tt); 83 int ca=1; 84 while(tt--) 85 { 86 printf("Case %d:\n",ca++); 87 scanf("%d%d",&n,&m); 88 scanf("%s",s+1); 89 s[0]=‘k‘; 90 build(root); 91 while(m--) 92 { 93 int op; 94 scanf("%d",&op); 95 if(op==0) 96 { 97 int l,r; 98 scanf("%d%d",&l,&r); 99 //printf("%d %d\n",l,r); 100 l++,r++; 101 int w=query(l,r,root); 102 printf("%d\n",w); 103 } 104 else 105 { 106 int x,val; 107 char c[10]; 108 scanf("%d%s",&x,c); 109 x++; 110 if(c[0]!=s[x]) s[x]=c[0],update(x,val,root); 111 112 } 113 } 114 } 115 }
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原文地址：http://www.cnblogs.com/cnblogs321114287/p/4711113.html
