#include <stddef.h>
#include <stdio.h>
#include <assert.h>
#include <vector>
#include "squares.h"
struct edge;
struct node {
std::vector<edge> edges;
int num_in;
} nodes[512];
struct edge {
node *nd;
int digit;
edge(node *n, int d) : nd(n), digit(d) {}
};
int lut[1024];
std::vector<int> paint(int n) {
std::vector<int> l(n+1);
l[n] = 10;
//Create a De Brujn sequence, and store the words in a look up table
for(int w = 0; w < 512; w++) {
nodes[w].edges.push_back(edge(nodes + ((w<<1) | 0), 0));
nodes[w].edges.push_back(edge(nodes + ((w<<1) | 1), 1));
nodes[w].num_in = 2;
}
node *nd = &nodes[0];
for(int i = 0; i < n; i++) {
//Choose an edge
std::vector<edge>::iterator ei;
if(nd->edges.size() == 0) break;
else if(nd->edges.size() == 1) ei = nd->edges.begin();
else {
if(nd->edges[0].nd->num_in == 1) ei = nd->edges.begin() + 1;
else ei = nd->edges.begin() + 0;
}
edge e = *ei;
//Delete the edge
nd->edges.erase(ei);
e.nd->num_in--;
//Advance along the edge
nd = e.nd;
//Update the LUT
int w = e.digit | ((nd - nodes) << 1);
lut[w] = i;
// printf("%d => %d [%d, %d]\n", w, i, e.digit, nd - nodes);
l[i] = e.digit;
}
return l;
}
int find_location(int n, std::vector<int> c) {
assert(c.size() == 10);
//Is at edge?
if(c[9] < 0) {
int p = 0;
while(c[p] >= 0) p++;
return n - p;
}
//Calculate word
int w = 0;
for(int i = 0; i < 10; i++) {
assert(c[i] >= 0);
w = (w << 1) | c[i];
}
//Lookup in LUT
return lut[w];
}
