传送门
题意: 有n层具有颜色的涂层,其每层的颜色由Ri, Ci,Bi三个指标对应6个长度的16进制数表示的。现问你 [li, ri]区间涂层的颜色重叠在一起是什么颜色。重叠规则如下:
* 若第i层的 wi==1,那么它只会显示自己的颜色(Ri,Gi,Bi)。
* 若第i层的 wi==2,那么它的颜色就是自身与先前层次的颜色的混和(min(Rp+Ri,255), min(Gp+Gi,255), min(Bp+Bi,255),当然颜色会有个上限255。
针对 p 次询问回答每个区间最后的颜色是什么。
思路:不难看出这就是在求 [li, ri]的颜色区间和,只不过换成了16进制数;且当出现 '1'时就会阻断颜色的传递,即所求颜色为 [max(pos, l), r]区间内的和,pos为最靠近 r 的前方 '1' 位置。
赛中还写了16->10和10->16进制之间转换的自定义函数,但是直接T到想吐!!!最后甚至只用到10->16的转换并于map初始化标记,还利用了快读和getchar(),依旧T到怀疑人生.......
代码实现:
#include<bitsdc++.h> #define LL long long #define me(ar) memset(ar, 0, sizeof ar) using namespace std; const int N = 1e5 + 5; inline int read(){ int x=0,f=1; char ch=getchar(); while(ch<'0'||ch>'9'){ if(ch=='-') f=-1; ch=getchar(); } while(ch>='0'&&ch<='9'){ x=(x<<1)+(x<<3)+(ch^48); ch=getchar(); } return x*f; } int T = 1; int n, p, l, r, sa, sb, sc; string s[N]; /ar s[N][10]; unordered_map<string, int> mp; unordered_map<int, string> mp2; int m[N], pos[N], a[N], b[N], c[N]; int pa[N], pb[N], pc[N], arr[N], num[N]; char h[16]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; void work1(int x){ int cnt = 0, w = x; string hh; while(x>0){ num[cnt++]=x%16; x /= 16; } if(cnt==1) hh += "0"; for(int i = cnt-1; ~i; i --){ int m = num[i]; hh += h[m]; } mp[hh] = w; mp2[w] = hh; } void Inint(){ for(int i = 1; i <= 255; i ++){ work1(i); } } signed main() { Inint(); T = read(); while(T --){ n = read(); p = read(); for(int i = 1; i <= n; i ++){ m[i] = read(); // scanf("%s", s[i]); // getchar(); for(int j = 1; j <= 6; j ++){ s[i] += getchar(); } // getchar(); // cout << "s: " << s[i] << endl; string ss1, ss2, ss3; ss1 += s[i][0]; ss1 += s[i][1]; a[i] = mp[ss1]; ss2 += s[i][2]; ss2 += s[i][3]; b[i] = mp[ss2]; ss3 += s[i][4]; ss3 += s[i][5]; c[i] = mp[ss3]; // cout << "a: " << a[i] << " b: " << b[i] << " c: " << c[i] << endl; pa[i] = pa[i-1]+a[i]; pb[i] = pb[i-1]+b[i]; pc[i] = pc[i-1]+c[i]; if(m[i]==1) pos[i] = i; else pos[i] = pos[i-1]; } while(p --){ l = read(); r = read(); if(pos[r]==r){ int le = s[r].size(); for(int i = 0; i < le; i ++) printf("%c", s[r][i]); } else if(pos[r]>l){ int ll = pos[r]; sa = pa[r]-pa[ll-1], sb = pb[r]-pb[ll-1], sc = pc[r]-pc[ll-1]; sa = min(sa, 255), sb = min(sb, 255), sc = min(sc, 255); int la = mp2[sa].size(), lb = mp2[sb].size(), lc = mp2[sc].size(); for(int i = 0; i < la; i ++) printf("%c", mp2[sa][i]); for(int i = 0; i < lb; i ++) printf("%c", mp2[sb][i]); for(int i = 0; i < lc; i ++) printf("%c", mp2[sc][i]); } else { sa = pa[r]-pa[l-1], sb = pb[r]-pb[l-1], sc = pc[r]-pc[l-1]; sa = min(sa, 255), sb = min(sb, 255), sc = min(sc, 255); int la = mp2[sa].size(), lb = mp2[sb].size(), lc = mp2[sc].size(); for(int i = 0; i < la; i ++) printf("%c", mp2[sa][i]); for(int i = 0; i < lb; i ++) printf("%c", mp2[sb][i]); for(int i = 0; i < lc; i ++) printf("%c", mp2[sc][i]); } puts(""); } } return 0; }
呜呜呜~赛后深刻反思,不该一直纠结一个思路和一份代码硬磕,及时转换思想很重要!!
其实此题在进制之间的转换只涉及到两位数,每次利用的时候临时计算一下反而比规范的自定义函数更省时;再者去掉自定义函数后甚至可以利用纯C语言编写最简洁的程序,没有了string和map肯定更省时。
AC代码:
#include<iostream> #include<algorithm> #include<unordered_map> #define LL long long #define me(ar) memset(ar, 0, sizeof ar) using namespace std; const int N = 1e5 + 5; inline int read(){ int x=0,f=1; char ch=getchar(); while(ch<'0'||ch>'9'){ if(ch=='-') f=-1; ch=getchar(); } while(ch>='0'&&ch<='9'){ x=(x<<1)+(x<<3)+(ch^48); ch=getchar(); } return x*f; } int T = 1; int n, p, l, r, a, b, c, sa, sb, sc; char s[10]; int m[N], pos[N], pa[N], pb[N], pc[N]; char h[18]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; int matche(char o){ if('0'<=o&&o<='9') return o-'0'; else return o-'A'+10; } signed main() { T = read(); while(T --){ n = read(); p = read(); for(int i = 1; i <= n; i ++){ m[i] = read(); scanf("%s", s); a = matche(s[0])*16+matche(s[1]); b = matche(s[2])*16+matche(s[3]); c = matche(s[4])*16+matche(s[5]); pa[i] = pa[i-1]+a; pb[i] = pb[i-1]+b; pc[i] = pc[i-1]+c; if(m[i]==1) pos[i] = i; else pos[i] = pos[i-1]; } while(p --){ l = read(); r = read(); if(pos[r]>l) l = pos[r]; sa = pa[r]-pa[l-1], sb = pb[r]-pb[l-1], sc = pc[r]-pc[l-1]; sa = min(sa, 255), sb = min(sb, 255), sc = min(sc, 255); printf("%c%c", h[sa/16], h[sa%16]); printf("%c%c", h[sb/16], h[sb%16]); printf("%c%c", h[sc/16], h[sc%16]); puts(""); } } return 0; }