输入输出样例
输入 #1
3 3 1 000 00- 1 00- 0-+ 2 0-- -++
输出 #1
View Code
8
思路
为啥会有网络流的tag
wa了5发感觉怎么建图都不对
一看都是状压最短路
打了个dijRE了
发现好像边太多
看别人都用的spfa莽，干脆我也莽一发好了
大家都知道spfa的核心就是边建图边松弛
如何建图：
因为对于第 i 个错误来说，只存在‘待修复’和‘已修复’两种状态
为了方便枚举，对状态进行压缩成一个整数来枚举
因为可能成环，显然状压dp很难处理这类问题
考虑用spfa来解决
对于每个错误，来枚举每个可能和他连的边
只要当前点 u 和 b1[i] 与运算为 b1[i] ，并且与 b2[i] 与为 0 说明此错误满足要求
再判断这条边的终点
先让 u 与 f1[i] 或（这里一定要先或因为后面要和 f1[i] 异或来使 u 上 f1[i] 的范围都清0）再与 f2[i] 或最后和 f1[i] 异或来清零这个区间
松弛就没啥好说的了，毕竟起终点都确立下来了
CODE
1 #include <bits/stdc++.h> 2 #define dbg(x) cout << #x << "=" << x << endl 3 #define eps 1e-8 4 #define pi acos(-1.0) 5 6 using namespace std; 7 typedef long long LL; 8 9 const int inf = 0x7f7f7f7f; 10 11 template<class T>inline void read(T &res) 12 { 13 char c;T flag=1; 14 while((c=getchar())<'0'||c>'9')if(c=='-')flag=-1;res=c-'0'; 15 while((c=getchar())>='0'&&c<='9')res=res*10+c-'0';res*=flag; 16 } 17 18 namespace _buff { 19 const size_t BUFF = 1 << 19; 20 char ibuf[BUFF], *ib = ibuf, *ie = ibuf; 21 char getc() { 22 if (ib == ie) { 23 ib = ibuf; 24 ie = ibuf + fread(ibuf, 1, BUFF, stdin); 25 } 26 return ib == ie ? -1 : *ib++; 27 } 28 } 29 30 int qread() { 31 using namespace _buff; 32 int ret = 0; 33 bool pos = true; 34 char c = getc(); 35 for (; (c < '0' || c > '9') && c != '-'; c = getc()) { 36 assert(~c); 37 } 38 if (c == '-') { 39 pos = false; 40 c = getc(); 41 } 42 for (; c >= '0' && c <= '9'; c = getc()) { 43 ret = (ret << 3) + (ret << 1) + (c ^ 48); 44 } 45 return pos ? ret : -ret; 46 } 47 48 const int maxn = 1e6 + 7; 49 50 int n, m; 51 52 int b1[maxn], b2[maxn], f1[maxn], f2[maxn]; 53 int dis[maxn], val[maxn]; 54 bool vis[maxn]; 55 56 int spfa(int s) { 57 memset(vis, 0, sizeof(vis)); 58 memset(dis, 127, sizeof(dis)); 59 dis[s] = 0; 60 queue<int> q; 61 while(!q.empty()) { 62 q.pop(); 63 } 64 q.push(s); 65 while(!q.empty()) { 66 int u = q.front(); 67 q.pop(); 68 int v = 0; 69 vis[u] = false; 70 for ( int i = 1; i <= m; ++i ) { 71 if((b1[i] & u) == b1[i] && (b2[i] & u) == 0) { 72 v = ((u | f1[i]) | f2[i]) ^ f1[i]; 73 if(dis[u] + val[i] < dis[v]) { 74 dis[v] = dis[u] + val[i]; 75 if(!vis[v]) { 76 vis[v] = true; 77 q.push(v); 78 } 79 } 80 } 81 } 82 } 83 //dbg(dis[0]); 84 return dis[0]; 85 } 86 87 int main() 88 { 89 read(n); read(m); 90 for ( int i = 1; i <= m; ++i ) { 91 read(val[i]); 92 string b, f; 93 cin >> b; 94 cin >> f; 95 b1[i] = b2[i] = f1[i] = f2[i] = 0; 96 for ( int j = 0; j < n; ++j ) { 97 if(b[j] == '+') { 98 b1[i] |= (1 << j); 99 } 100 else if(b[j] == '-') { 101 b2[i] |= (1 << j); 102 } 103 if(f[j] == '-') { 104 f1[i] |= (1 << j); 105 } 106 else if(f[j] == '+') { 107 f2[i] |= (1 << j); 108 } 109 } 110 } 111 int ans = spfa((1 << n) - 1); 112 if(ans == inf) { 113 cout << 0 << endl; 114 } 115 else { 116 cout << dis[0] << endl; 117 } 118 return 0; 119 }
#include <bits/stdc++.h>
#define dbg(x) cout << #x << "=" << x << endl
#define eps 1e-8
#define pi acos(-1.0)
using namespace std;
typedef long long LL;
const int inf = 0x7f7f7f7f;
template<class T>inline void read(T &res)
{
char c;T flag=1;
while((c=getchar())<'0'||c>'9')if(c=='-')flag=-1;res=c-'0';
while((c=getchar())>='0'&&c<='9')res=res*10+c-'0';res*=flag;
}
namespace _buff {
const size_t BUFF = 1 << 19;
char ibuf[BUFF], *ib = ibuf, *ie = ibuf;
char getc() {
if (ib == ie) {
ib = ibuf;
ie = ibuf + fread(ibuf, 1, BUFF, stdin);
}
return ib == ie ? -1 : *ib++;
}
}
int qread() {
using namespace _buff;
int ret = 0;
bool pos = true;
char c = getc();
for (; (c < '0' || c > '9') && c != '-'; c = getc()) {
assert(~c);
}
if (c == '-') {
pos = false;
c = getc();
}
for (; c >= '0' && c <= '9'; c = getc()) {
ret = (ret << 3) + (ret << 1) + (c ^ 48);
}
return pos ? ret : -ret;
}
const int maxn = 1e6 + 7;
int n, m;
int b1[maxn], b2[maxn], f1[maxn], f2[maxn];
int dis[maxn], val[maxn];
bool vis[maxn];
int spfa(int s) {
memset(vis, 0, sizeof(vis));
memset(dis, 127, sizeof(dis));
dis[s] = 0;
queue<int> q;
while(!q.empty()) {
q.pop();
}
q.push(s);
while(!q.empty()) {
int u = q.front();
q.pop();
int v = 0;
vis[u] = false;
for ( int i = 1; i <= m; ++i ) {
if((b1[i] & u) == b1[i] && (b2[i] & u) == 0) {
v = ((u | f1[i]) | f2[i]) ^ f1[i];
if(dis[u] + val[i] < dis[v]) {
dis[v] = dis[u] + val[i];
if(!vis[v]) {
vis[v] = true;
q.push(v);
}
}
}
}
}
//dbg(dis[0]);
return dis[0];
}
int main()
{
read(n); read(m);
for ( int i = 1; i <= m; ++i ) {
read(val[i]);
string b, f;
cin >> b;
cin >> f;
b1[i] = b2[i] = f1[i] = f2[i] = 0;
for ( int j = 0; j < n; ++j ) {
if(b[j] == '+') {
b1[i] |= (1 << j);
}
else if(b[j] == '-') {
b2[i] |= (1 << j);
}
if(f[j] == '-') {
f1[i] |= (1 << j);
}
else if(f[j] == '+') {
f2[i] |= (1 << j);
}
}
}
int ans = spfa((1 << n) - 1);
if(ans == inf) {
cout << 0 << endl;
}
else {
cout << dis[0] << endl;
}
return 0;
}