
本题中从3000到3999,一共有1000个数字,分别如下:
3000,3001,3002,3003……3009,3010,3011……3099
3100,3101,3102,3103……3109,3110,3111……3199
3200,3201,3202,3203……3209,3210,3211……3299
3300,3301,3302,3303……3309,3310,3311……3399
……
3900,3901,3902,3903……3909,3910,3911……3999,

本题中从3000到3999,一共有1000个数字,分别如下:
3000,3001,3002,3003……3009,3010,3011……3099
3100,3101,3102,3103……3109,3110,3111……3199
3200,3201,3202,3203……3209,3210,3211……3299
3300,3301,3302,3303……3309,3310,3311……3399
……
3900,3901,3902,3903……3909,3910,3911……3999,