aoc 15 dijkstra (pour pardouin)

def dijkstra(grid, target, start=(0, 0), risk=0):
    queue = [(risk, start)]
    min_risk = {start: risk}
    visited = {start}

    while queue:
        risk, (x, y) = heapq.heappop(queue)
        if (x, y) == target:
            return risk
        for neigh in ((x + 1, y), (x, y + 1), (x - 1, y), (x, y - 1)):
            if neigh not in grid or neigh in visited: continue
            visited.add(neigh)
            new_risk = risk + grid[neigh]
            if new_risk < min_risk.get(neigh, 999999):
                min_risk[neigh] = new_risk
                heapq.heappush(queue, (new_risk, neigh))