[ImgBot] Optimize images

[ImgBot] Optimize images

*Total -- 5,512.15kb -> 3,997.08kb (27.49%)

/docs/misc/images/CDQ-5.png -- 6.01kb -> 0.55kb (90.9%)
/docs/string/images/sa1.png -- 9.52kb -> 2.02kb (78.81%)
/docs/string/images/sa2.png -- 11.93kb -> 2.98kb (75.02%)
/docs/string/images/sa3.png -- 12.19kb -> 3.19kb (73.86%)
/docs/graph/images/bcc-counterexample.png -- 32.46kb -> 9.94kb (69.39%)
/docs/ds/images/lct9.png -- 19.67kb -> 6.99kb (64.48%)
/docs/ds/images/segt12.png -- 39.34kb -> 14.14kb (64.07%)
/docs/graph/images/1341373589_4609.png -- 20.08kb -> 7.62kb (62.07%)
/docs/ds/images/segt14.png -- 44.87kb -> 17.33kb (61.38%)
/docs/math/images/game1.png -- 49.02kb -> 19.12kb (60.99%)
/docs/misc/images/order.png -- 47.14kb -> 18.64kb (60.46%)
/docs/ds/images/segt7.png -- 52.15kb -> 21.11kb (59.51%)
/docs/ds/images/segt11.png -- 39.14kb -> 16.07kb (58.95%)
/docs/geometry/images/2d-seg1.png -- 12.76kb -> 5.26kb (58.73%)
/docs/graph/images/mst2.png -- 8.27kb -> 3.42kb (58.67%)
/docs/ds/images/segt10.png -- 23.47kb -> 9.77kb (58.36%)
/docs/ds/images/segt15.png -- 38.83kb -> 16.39kb (57.79%)
/docs/ds/images/segt13.png -- 21.57kb -> 9.11kb (57.76%)
/docs/graph/images/mst3.png -- 14.62kb -> 6.21kb (57.49%)
/docs/ds/images/segt9.png -- 18.23kb -> 7.76kb (57.42%)
/docs/graph/images/mst4.png -- 19.80kb -> 8.45kb (57.34%)
/docs/ds/images/segt4.png -- 31.12kb -> 13.29kb (57.29%)
/docs/misc/images/CDQ-3.png -- 0.86kb -> 0.37kb (56.92%)
/docs/ds/images/segt5.png -- 61.92kb -> 27.23kb (56.03%)
/docs/ds/images/segt8.png -- 17.64kb -> 7.81kb (55.72%)
/docs/ds/images/segt3.png -- 27.89kb -> 12.39kb (55.55%)
/docs/graph/images/mst1.png -- 22.28kb -> 9.92kb (55.49%)
/docs/ds/images/segt6.png -- 24.49kb -> 11.24kb (54.11%)
/docs/misc/images/cdq-divide1.png -- 14.54kb -> 6.72kb (53.75%)
/docs/misc/images/CDQ-1.png -- 14.54kb -> 6.72kb (53.75%)
/docs/graph/flow/images/node2.png -- 10.65kb -> 4.97kb (53.33%)
/docs/misc/images/24620.png -- 12.30kb -> 5.86kb (52.37%)
/docs/misc/images/24909.png -- 12.76kb -> 6.09kb (52.27%)
/docs/graph/flow/images/node1.png -- 6.29kb -> 3.08kb (51.12%)
/docs/images/wordArt.png -- 158.98kb -> 77.99kb (50.94%)
/docs/ds/images/bit1.png -- 39.13kb -> 20.46kb (47.73%)
/docs/ds/images/dividing2.png -- 2.58kb -> 1.43kb (44.63%)
/docs/ds/images/dividing1.png -- 7.11kb -> 3.96kb (44.31%)
/docs/misc/images/CDQ-2.png -- 1.55kb -> 0.89kb (42.53%)
/docs/intro/images/WSL4.png -- 116.36kb -> 67.58kb (41.92%)
/docs/intro/images/WSL3.png -- 81.51kb -> 48.47kb (40.54%)
/docs/misc/images/CDQ-4.png -- 3.12kb -> 1.87kb (40.21%)
/docs/intro/images/WSL22.png -- 213.06kb -> 131.71kb (38.18%)
/docs/intro/images/WSL5.png -- 89.72kb -> 56.02kb (37.57%)
/docs/intro/images/WSL2.png -- 70.59kb -> 44.30kb (37.24%)
/docs/math/images/容斥原理1.png -- 6.04kb -> 3.80kb (37.11%)
/docs/intro/images/WSL9.png -- 25.38kb -> 16.18kb (36.24%)
/docs/intro/images/WSL17.png -- 37.27kb -> 24.03kb (35.53%)
/docs/ds/images/st1.png -- 74.52kb -> 48.46kb (34.97%)
/docs/math/images/complex-1.png -- 23.05kb -> 15.02kb (34.83%)
/docs/graph/images/bcc-2.png -- 38.75kb -> 25.49kb (34.21%)
/docs/graph/images/bcc-1.png -- 36.41kb -> 24.03kb (34.01%)
/docs/misc/images/24919.png -- 18.99kb -> 12.67kb (33.28%)
/docs/ds/images/segt2.png -- 32.23kb -> 21.72kb (32.6%)
/docs/intro/images/WSL6.png -- 40.48kb -> 27.58kb (31.87%)
/docs/intro/images/WSL14.png -- 19.58kb -> 13.49kb (31.1%)
/docs/ds/images/lct1.png -- 53.02kb -> 36.84kb (30.51%)
/docs/geometry/images/2d-intersection.png -- 19.31kb -> 13.49kb (30.12%)
/docs/intro/images/WSL1.png -- 31.73kb -> 22.28kb (29.8%)
/docs/ds/images/segt1.png -- 25.85kb -> 18.20kb (29.58%)
/docs/ds/images/lct2.png -- 53.87kb -> 38.97kb (27.65%)
/docs/ds/images/lct7.png -- 48.01kb -> 34.75kb (27.62%)
/docs/intro/images/WSL23.png -- 46.80kb -> 34.20kb (26.92%)
/docs/intro/images/WSL18.png -- 28.70kb -> 20.98kb (26.88%)
/docs/graph/images/bi-graph.png -- 11.90kb -> 8.76kb (26.41%)
/docs/ds/images/lct6.png -- 44.96kb -> 33.13kb (26.31%)
/docs/string/images/manacher3.png -- 76.71kb -> 56.66kb (26.14%)
/docs/ds/images/lct8.png -- 64.76kb -> 48.25kb (25.5%)
/docs/graph/images/flow1.png -- 35.77kb -> 26.72kb (25.31%)
/docs/string/images/manacher1.png -- 14.65kb -> 11.08kb (24.39%)
/docs/ds/images/lct5.png -- 20.77kb -> 15.88kb (23.55%)
/docs/ds/images/lct10.png -- 10.86kb -> 8.30kb (23.52%)
/docs/intro/images/horrorstories.txt.jpg -- 25.87kb -> 20.27kb (21.62%)
/docs/ds/images/lct3.png -- 42.40kb -> 33.50kb (20.98%)
/docs/geometry/images/2d-seg2.png -- 16.83kb -> 13.61kb (19.11%)
/docs/intro/images/arbiter_problem.png -- 8.73kb -> 7.07kb (19.05%)
/docs/ds/images/persistent-seg.png -- 30.98kb -> 25.08kb (19.04%)
/docs/intro/images/WSL20.png -- 770.84kb -> 624.16kb (19.03%)
/docs/ds/images/splay1.png -- 102.91kb -> 84.30kb (18.08%)
/docs/intro/images/WSL10.png -- 10.69kb -> 8.87kb (16.99%)
/docs/intro/images/arbiter_test.png -- 46.85kb -> 38.90kb (16.96%)
/docs/ds/images/lct4.png -- 17.74kb -> 14.89kb (16.04%)
/docs/intro/images/arbiter_home.png -- 261.05kb -> 220.06kb (15.7%)
/docs/intro/images/WSL16.png -- 42.35kb -> 35.71kb (15.67%)
/docs/intro/images/arbiter_pretest.png -- 45.48kb -> 38.75kb (14.81%)
/docs/intro/images/WSL21.png -- 594.83kb -> 514.85kb (13.45%)
/docs/intro/images/WSL15.png -- 425.29kb -> 373.28kb (12.23%)
/docs/string/images/manacher2.png -- 37.08kb -> 32.61kb (12.04%)
/docs/intro/images/arbiter_addproblem.png -- 19.25kb -> 16.95kb (11.97%)
/docs/ds/images/splay2.png -- 138.19kb -> 122.46kb (11.38%)
/docs/intro/images/WSL11.png -- 8.78kb -> 7.81kb (11.12%)
/docs/ds/images/kuaizhuanglianbiao.png -- 26.90kb -> 23.95kb (10.97%)
/docs/intro/images/WSL19.png -- 8.27kb -> 7.39kb (10.57%)
/docs/intro/images/WSL13.png -- 10.70kb -> 9.79kb (8.45%)
/docs/intro/images/WSL7.png -- 1.92kb -> 1.77kb (7.85%)
/docs/intro/images/airline2.png -- 7.78kb -> 7.19kb (7.49%)
/docs/ds/images/vtree10.png -- 3.16kb -> 2.98kb (5.54%)
/docs/ds/images/vtree5.png -- 5.94kb -> 5.62kb (5.49%)
/docs/ds/images/vtree2.png -- 5.06kb -> 4.78kb (5.48%)
/docs/ds/images/vtree11.png -- 3.16kb -> 2.99kb (5.4%)
/docs/dp/images/dag-babylon.png -- 72.14kb -> 68.41kb (5.17%)
/docs/ds/images/vtree3.png -- 5.25kb -> 4.99kb (4.95%)
/docs/intro/images/airline1.png -- 3.09kb -> 2.96kb (4.39%)
/docs/ds/images/vtree13.png -- 4.05kb -> 3.88kb (4.31%)
/docs/intro/images/WSL12.png -- 3.84kb -> 3.68kb (4.12%)
/docs/graph/images/flow2.png -- 64.24kb -> 61.63kb (4.06%)
/docs/math/images/fft3.jpg -- 10.69kb -> 10.27kb (3.9%)
/docs/ds/images/vtree12.png -- 3.74kb -> 3.59kb (3.84%)
/docs/ds/images/vtree1.png -- 3.84kb -> 3.70kb (3.71%)
/docs/math/images/fft2.jpg -- 20.45kb -> 19.71kb (3.6%)
/docs/basic/images/bet.png -- 21.93kb -> 21.17kb (3.46%)
/docs/ds/images/vtree4.png -- 5.52kb -> 5.33kb (3.36%)
/docs/ds/images/vtree6.png -- 4.56kb -> 4.43kb (3%)
/docs/ds/images/vtree8.png -- 4.89kb -> 4.76kb (2.6%)
/docs/intro/images/WSL8.png -- 17.60kb -> 17.17kb (2.47%)
/docs/math/images/fft1.jpg -- 15.56kb -> 15.21kb (2.21%)
/docs/ds/images/vtree9.png -- 4.56kb -> 4.46kb (2.16%)
/docs/ds/images/vtree7.png -- 4.78kb -> 4.71kb (1.49%)