Good Bye 2014 B. New Year Permutation 并查集 最短路 floyed算法
2015-08-22 13:54
489 查看
B. New Year Permutation
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
User ainta has a permutation p1, p2, ..., pn.
As the New Year is coming, he wants to make his permutation as pretty as possible.
Permutation a1, a2, ..., an is prettier than
permutation b1, b2, ..., bn,
if and only if there exists an integer k (1 ≤ k ≤ n)
wherea1 = b1, a2 = b2, ..., ak - 1 = bk - 1 and ak < bk all
holds.
As known, permutation p is so sensitive that it could be only modified by swapping two distinct elements. But swapping two elements is
harder than you think. Given an n × n binary matrix A,
user ainta can swap the values of pi and pj (1 ≤ i, j ≤ n, i ≠ j)
if and only ifAi, j = 1.
Given the permutation p and the matrix A,
user ainta wants to know the prettiest permutation that he can obtain.
Input
The first line contains an integer n (1 ≤ n ≤ 300)
— the size of the permutation p.
The second line contains n space-separated integers p1, p2, ..., pn —
the permutation p that user ainta has. Each integer between 1and n occurs
exactly once in the given permutation.
Next n lines describe the matrix A.
The i-th line contains n characters
'0' or '1' and describes the i-th
row of A. The j-th
character of thei-th line Ai, j is
the element on the intersection of the i-th row and the j-th
column of A. It is guaranteed that, for all integers i, j where1 ≤ i < j ≤ n, Ai, j = Aj, i holds.
Also, for all integers i where 1 ≤ i ≤ n, Ai, i = 0 holds.
Output
In the first and only line, print n space-separated integers, describing the prettiest permutation that can be obtained.
Sample test(s)
input
output
input
output
Note
In the first sample, the swap needed to obtain the prettiest permutation is: (p1, p7).
In the second sample, the swaps needed to obtain the prettiest permutation is (p1, p3), (p4, p5), (p3, p4).
A permutation p is a sequence of integers p1, p2, ..., pn,
consisting of n distinct positive integers, each of them doesn't exceed n.
Thei-th element of the permutation p is
denoted as pi.
The size of the permutation p is denoted as n.
题意,给出一个初始数列,再给出一个矩阵,确定i j位置是否可以交换。要求最小字典序的数列。
首先给一个简单的想法,如果知道任意两点是否可以交换(包括间接交换),那么,我们只需要从最小的数开始一个一个的确定最小的位置 ,就可以得出答案了。如果要知道间接是否可交换,相当于求,任意两点间,最短路是否可为1,用floyed算法求出,复杂度为o(n ^3)
#define N 305
#define M 100005
#define maxn 205
#define MOD 1000000000000000007
int n,b
,p
,a
;
char str
;
void prin(){
FI(n)
if(!i)
printf("%d",p[i] + 1);
else
printf(" %d",p[i] + 1);
printf("\n");
}
int main()
{
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
while(S(n)!=EOF)
{
FI(n) {
S(p[i]);
p[i]--;
a[p[i]] = i;
}
FI(n) {
SS(str);
for(int j = 0;str[j] != '\0';j++){
b[i][j] = str[j] == '1'?1:0;
}
}
for(int i = 0;i<n;i++)
for(int j = 0;j<n;j++)
for(int k = 0;k<n;k++){
b[j][k] = max(b[j][k],b[j][i] & b[i][k]);
}
FI(n){
for(int j = 0;j<a[i];j++){
if(p[j] > i && b[a[i]][j]){
int t = p[j],t2 = a[i];
p[j] = i;
p[t2] = t;
a[i] = j;
a[t] = t2;
break;
}
}
}
prin();
}
//fclose(stdin);
//fclose(stdout);
return 0;
}
第二种方法。用并查集优化,由于,在同一个集合内的点,明显,只需要从小到大排(因为同一集合,经过一点变换,一定可以生成各种排列),就一定是最优解了。复杂度,为O(n * n);
#define N 305
#define M 100005
#define maxn 205
#define MOD 1000000000000000007
int n,p
,num
;
char str
;
vector<int> g
;
struct UnionFind{
int fa
;
int findFa(int x){
return fa[x] == x? x:fa[x] = findFa(fa[x]);
}
void init(int n){
FI(n) fa[i] = i;
}
void Uni(int a,int b){
fa[findFa(a)] = findFa(b);
}
}U;
int main()
{
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
while(S(n)!=EOF)
{
U.init(n);
fill(num,0);
FI(n) {
S(p[i]);
p[i]--;
}
FI(n) {
SS(str);
for(int j = 0;str[j] != '\0';j++){
if(str[j] == '1'){
U.Uni(i,j);
}
}
}
FI(n) g[U.findFa(i)].push_back(p[i]);
FI(n) if(U.findFa(i) == i) sort(g[i].begin(),g[i].end());
FI(n){
int fa = U.findFa(i);
int t = g[fa][num[fa]++];
if(!i) printf("%d",t + 1);
else printf(" %d",t + 1);
}
printf("\n");
}
//fclose(stdin);
//fclose(stdout);
return 0;
}
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
User ainta has a permutation p1, p2, ..., pn.
As the New Year is coming, he wants to make his permutation as pretty as possible.
Permutation a1, a2, ..., an is prettier than
permutation b1, b2, ..., bn,
if and only if there exists an integer k (1 ≤ k ≤ n)
wherea1 = b1, a2 = b2, ..., ak - 1 = bk - 1 and ak < bk all
holds.
As known, permutation p is so sensitive that it could be only modified by swapping two distinct elements. But swapping two elements is
harder than you think. Given an n × n binary matrix A,
user ainta can swap the values of pi and pj (1 ≤ i, j ≤ n, i ≠ j)
if and only ifAi, j = 1.
Given the permutation p and the matrix A,
user ainta wants to know the prettiest permutation that he can obtain.
Input
The first line contains an integer n (1 ≤ n ≤ 300)
— the size of the permutation p.
The second line contains n space-separated integers p1, p2, ..., pn —
the permutation p that user ainta has. Each integer between 1and n occurs
exactly once in the given permutation.
Next n lines describe the matrix A.
The i-th line contains n characters
'0' or '1' and describes the i-th
row of A. The j-th
character of thei-th line Ai, j is
the element on the intersection of the i-th row and the j-th
column of A. It is guaranteed that, for all integers i, j where1 ≤ i < j ≤ n, Ai, j = Aj, i holds.
Also, for all integers i where 1 ≤ i ≤ n, Ai, i = 0 holds.
Output
In the first and only line, print n space-separated integers, describing the prettiest permutation that can be obtained.
Sample test(s)
input
7 5 2 4 3 6 7 1 0001001 0000000 0000010 1000001 0000000 0010000 1001000
output
1 2 4 3 6 7 5
input
5 4 2 1 5 3 00100 00011 10010 01101 01010
output
1 2 3 4 5
Note
In the first sample, the swap needed to obtain the prettiest permutation is: (p1, p7).
In the second sample, the swaps needed to obtain the prettiest permutation is (p1, p3), (p4, p5), (p3, p4).
A permutation p is a sequence of integers p1, p2, ..., pn,
consisting of n distinct positive integers, each of them doesn't exceed n.
Thei-th element of the permutation p is
denoted as pi.
The size of the permutation p is denoted as n.
题意,给出一个初始数列,再给出一个矩阵,确定i j位置是否可以交换。要求最小字典序的数列。
首先给一个简单的想法,如果知道任意两点是否可以交换(包括间接交换),那么,我们只需要从最小的数开始一个一个的确定最小的位置 ,就可以得出答案了。如果要知道间接是否可交换,相当于求,任意两点间,最短路是否可为1,用floyed算法求出,复杂度为o(n ^3)
#define N 305
#define M 100005
#define maxn 205
#define MOD 1000000000000000007
int n,b
,p
,a
;
char str
;
void prin(){
FI(n)
if(!i)
printf("%d",p[i] + 1);
else
printf(" %d",p[i] + 1);
printf("\n");
}
int main()
{
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
while(S(n)!=EOF)
{
FI(n) {
S(p[i]);
p[i]--;
a[p[i]] = i;
}
FI(n) {
SS(str);
for(int j = 0;str[j] != '\0';j++){
b[i][j] = str[j] == '1'?1:0;
}
}
for(int i = 0;i<n;i++)
for(int j = 0;j<n;j++)
for(int k = 0;k<n;k++){
b[j][k] = max(b[j][k],b[j][i] & b[i][k]);
}
FI(n){
for(int j = 0;j<a[i];j++){
if(p[j] > i && b[a[i]][j]){
int t = p[j],t2 = a[i];
p[j] = i;
p[t2] = t;
a[i] = j;
a[t] = t2;
break;
}
}
}
prin();
}
//fclose(stdin);
//fclose(stdout);
return 0;
}
第二种方法。用并查集优化,由于,在同一个集合内的点,明显,只需要从小到大排(因为同一集合,经过一点变换,一定可以生成各种排列),就一定是最优解了。复杂度,为O(n * n);
#define N 305
#define M 100005
#define maxn 205
#define MOD 1000000000000000007
int n,p
,num
;
char str
;
vector<int> g
;
struct UnionFind{
int fa
;
int findFa(int x){
return fa[x] == x? x:fa[x] = findFa(fa[x]);
}
void init(int n){
FI(n) fa[i] = i;
}
void Uni(int a,int b){
fa[findFa(a)] = findFa(b);
}
}U;
int main()
{
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
while(S(n)!=EOF)
{
U.init(n);
fill(num,0);
FI(n) {
S(p[i]);
p[i]--;
}
FI(n) {
SS(str);
for(int j = 0;str[j] != '\0';j++){
if(str[j] == '1'){
U.Uni(i,j);
}
}
}
FI(n) g[U.findFa(i)].push_back(p[i]);
FI(n) if(U.findFa(i) == i) sort(g[i].begin(),g[i].end());
FI(n){
int fa = U.findFa(i);
int t = g[fa][num[fa]++];
if(!i) printf("%d",t + 1);
else printf(" %d",t + 1);
}
printf("\n");
}
//fclose(stdin);
//fclose(stdout);
return 0;
}
相关文章推荐
- 基于Google Material Design设计开发,模块包括图片浏览,视频爽看 ,音乐轻听以及二维码扫描
- Codeforces Round #313 (Div. 2) C. Gerald's Hexagon
- Go 1.5中值得关注的几个变化
- 投资问题,lingo程序
- Go 的垃圾回收机制在实践中有哪些需要注意的地方?
- Go语言教程汇总
- Go语言中使用panic和recover简化错误处理
- Go获取命令行参数及信号量处理
- Go各种类型转换及函数的高级用法
- Go语言中的复合类型及面向对象思想
- HDU 2521 反素数
- oc NSDate / Category类目 / 延展
- Algorithm类介绍(core)
- NYOJ 546 Divideing Jewels ( 背包+二进制优化)
- UVA 11090 Going in Cycle!! SPFA判断负环+二分
- window7安装django
- Go语言相关图书推荐
- [c] sdnuoj1147Pythagoras's Revenge
- Google浏览器清除缓存快捷键
- RAFT algorithm