if (left === n - 1) return 0;
Secret Sauce #1: Two-Level Routing
，详情可参考同城约会
Continue reading...
The conditions you have to meet are specific to the color-coded spaces. For example, if it provides a single number, every side of a tile in that space must add up to the number provided. It is possible – and common – for only half a tile to be within a color-coded space.
)(cartSummary);